I think you may be trying to read far too much into this verse that the grammar won't support. The first translation of each verse in its simplest form is really the best translation and says pretty much everything the grammar allows. The rest is reading more into the text than the grammar would support. I also think you are misunderstanding some of the grammar.
The Qal says the least about the verbal action possible. That is essentially what is meant by saying that "notions of causation are absent."1 You cannot turn around and try to say that it means permissive, because even this somewhat implies passive causation. The Qal stem says the least possible. Any attempts to infer anything beyond the simple meaning of the verb is taking it too far. You are reading other grammatical constructions into the text where they are not justified. So a proposed translation of each verse is as follows, along with a detailed breakdown offering support for each reading:
Genesis 1:3
וַיֹּ֥אמֶר אֱלֹהִ֖ים יְהִ֣י א֑וֹר וַֽיְהִי־אֽוֹר׃
וַיֹּ֥אמֶר ("and he said") is a Qal wayyiqṭōl (prefixed/imperfect sequential) 3rd person masculine singular verb. It commonly introduces discourse/speech.
אֱלֹהִ֖ים ("God") is a common masculine plural absolute proper noun.
יְהִ֣י ("Let there be") is a Qal yiqṭōl (imperfect) 3rd person masculine singular jussive verb. The jussive refers to a third person expression of volition (wish/desire), i.e. an indirect command.
א֑וֹר ("light") is a common singular absolute noun.
וַֽיְהִי ("and there was") is another Qal wayyiqṭōl (prefixed/imperfect sequential) 3rd person masculine singular verb. It is also a fairly common verb construction, meaning "and there was," "and there came to pass," or "and it happened."
אֽוֹר ("light") is a common singular absolute noun.
The NET translators' notes point out:
“Let there be” is the short jussive form of the verb “to be”; the
following expression “and there was” is the short preterite form of
the same verb. As such, יְהִי (yéhi) and וַיְהִי (vayéhi) form a
profound wordplay to express both the calling into existence and the
complete fulfillment of the divine word.2
Keep in mind that imperfect in Hebrew does not imply tense (biblical Hebrew has no tense as in English). Rather, it implies aspect.
That is, it views the action of the verb from the inside or from the
perspective of the action’s unfolding. This imperfective aspect can
speak of (depending on context) habitual actions, actions in progress,
or even completed actions that have unfolding, ongoing results. The
term ‘imperfective’ does not refer to tense, though. Biblical Hebrew
does not have tense like English or Greek (time of action is conveyed
by context). ‘Imperfective’ refers to the kind of action being
described, not the time of the action. An action can be viewed in
process in the past (“was walking”), the present (“is walking”), or
even the future (“will be walking”). When the context dictates, the
prefixed conjugation also conveys the indicative mood, the mood of
reality. This conjugation is often referred to as the yiqtol
conjugation. [Note, some grammars do teach a tense-based view of the
Hebrew verb, and this form sometimes is labeled the ‘future’ tense,
with the wayyiqtol labeled the ‘inverted-future’.]3
So a proposed translation would be:
And God said, "Let there be light." And there was light.
To try to say much more beyond that would be to read too much into the grammar.
Genesis 12:3
וַאֲבָֽרֲכָה֙ מְבָ֣רְכֶ֔יךָ וּמְקַלֶּלְךָ֖ אָאֹ֑ר וְנִבְרְכ֣וּ בְךָ֔ כֹּ֖ל מִשְׁפְּחֹ֥ת הָאֲדָמָֽה׃
וַאֲבָֽרֲכָה֙ ("And I will bless") is a Piel weyiqṭōl (imperfect) 1st person common singular cohortative verb. The cohortative refers to a first person expression of volition (wish/desire). Waltke & O'Connor point out that the Piel used to be thought to signify an intensification of the root verb's meaning,4 but this is no longer the scholarly consensus.5 They point out that "the meaning of the Piel stem is neither intensive nor causative (in the sense that it is practically equivalent in meaning to the Hiphil). Rather, it expresses the bringing about of a state."6
The piʿʿēl stem expresses the bringing about of a state. The object of
the piʿʿēl verb’s action “suffers the effect” of the action; i.e., it
is put into a state by the action. In the sentence “Bob flies the
plane,” the direct object [plane] is put into the state of flight by
the subject of the verb [Bob].7
מְבָ֣רְכֶ֔יךָ ("those who bless you") is a Piel masculine plural construct (with a 2nd person masculine singular pronominal suffix) participle. Literally "those blessing you."
Commenting on this first phrase, the NET translators state:
The Piel cohortative has as its object a Piel participle, masculine
plural. Since the LORD binds himself to Abram by covenant, those who
enrich Abram in any way share in the blessings.8
וּמְקַלֶּלְךָ֖ ("and him who curses you") is a Piel masculine singular construct (with a 2nd person masculine singular pronominal suffix) participle. Literally "and him [or 'the one'] cursing you." קלל in the Piel can mean "to designate as too lightweight; contemptible," or to "declare cursed, accursed."9
אָאֹ֑ר ("I will curse") is a yiqṭōl (imperfect) 1st person common singular verb. According to the NET translators, this implies obligation ("I must curse"):
In this part of God’s statement there are two significant changes that
often go unnoticed. First, the parallel and contrasting participle
מְקַלֶּלְךָ (méqallelkha) is now singular and not plural. All the
versions and a few Masoretic MSS read the plural. But if it had been
plural, there would be no reason to change it to the singular and
alter the parallelism. On the other hand, if it was indeed singular,
it is easy to see why the versions would change it to match the first
participle. The MT preserves the original reading: “the one who treats
you lightly.” The point would be a contrast with the lavish way that
God desires to bless many. The second change is in the vocabulary. The
English usually says, “I will curse those who curse you.” But there
are two different words for curse here. The first is קָלַל (qalal),
which means “to be light” in the Qal, and in the Piel “to treat
lightly, to treat with contempt, to curse.” The second verb is אָרַר
(’arar), which means “to banish, to remove from the blessing.” The
point is simple: Whoever treats Abram and the covenant with contempt
as worthless God will banish from the blessing. It is important also
to note that the verb is not a cohortative, but a simple imperfect.
Since God is binding himself to Abram, this would then be an
obligatory imperfect: “but the one who treats you with contempt I must
curse.”10
וְנִבְרְכ֣וּ ("and they shall be blessed") is a Niphal weqāṭal (perfect/suffixed sequential) 3rd person plural verb. The Niphal is generally translated into English as either passive ("they shall be blessed") or reflexive ("they shall bless themselves"), but this category of meaning actually has no direct correlation in the English language.11 The NET translators explain:
Theoretically the Niphal can be translated either as passive or
reflexive/reciprocal. (The Niphal of “bless” is only used in
formulations of the Abrahamic covenant. See Gen 12:2; 18:18; 28:14.)
Traditionally the verb is taken as passive here, as if Abram were
going to be a channel or source of blessing. But in later formulations
of the Abrahamic covenant (see Gen 22:18; 26:4) the Hitpael replaces
this Niphal form, suggesting a translation “will bless [i.e.,
“pronounce blessings on”] themselves [or “one another”].” The Hitpael
of “bless” is used with a reflexive/reciprocal sense in Deut 29:18; Ps
72:17; Isa 65:16; Jer 4:2. Gen 12:2 predicts that Abram will be held
up as a paradigm of divine blessing and that people will use his name
in their blessing formulae. For examples of blessing formulae
utilizing an individual as an example of blessing see Gen 48:20 and
Ruth 4:11.12
בְךָ֔ ("in/by you") is a suffixed 2nd person masculine singular pronoun.
כֹּ֖ל ("all") is a common singular construct noun.
מִשְׁפְּחֹ֥ת ("families of") is a common feminine plural construct noun.
הָאֲדָמָֽה ("the earth") is a common feminine singular absolute (definite with prefix הָ) noun.
So a proposed translation would be:
And I will bless those blessing you, and the one dishonoring you
[treating you lightly/contemptibly] I will [or must] curse. And in you all families of the
earth shall be blessed [or by you all families of the earth shall
bless themselves].
Conclusion
I hope this answers your question and clears up any confusion about the grammar and syntax of these verses. If not, please comment and I will do my best to understand what you are specifically asking.
Sources
1 Bruce K. Waltke and M. O'Connor, An Introduction to Biblical Hebrew Syntax (Winona Lake, IN: Eisenbrauns, 1990), 362.
2 Biblical Studies Press, The NET Bible First Edition Notes (Biblical Studies Press, 2006), Gen. 1:3.<
3 Michael S. Heiser and Vincent M. Setterholm, Glossary of Morpho-Syntactic Database Terminology (Logos Bible Software, 2013; 2013).
4 Waltke and O'Connor, 396 (396ff includes a discussion of the scholarly literature).
5 Ibid., 399ff.
6 Ibid., 399-400, emphasis mine.
7 Heiser and Setterholm.
8 Biblical Studies Press, Gen. 12:3.
9 Ludwig Koehler, Walter Baumgartner, M. E. J. Richardson and Johann Jakob Stamm, The Hebrew and Aramaic Lexicon of the Old Testament, electronic ed. (Leiden; New York: E.J. Brill, 1999), 1104.
10 Biblical Studies Press, Gen. 12:3.
11 Waltke and O'Connor, 378ff.
12 Biblical Studies Press, Gen. 12:3.
