What effects can apply to a creature inside a portable hole, from outside?

Question

^{Related question: Are you considered out of range of spells and weapons when inside the hole of a Portable Hole?}
(This question does not have an answer appropriate to the title. Also, the question only addresses weapons & spellcasting across the connection point; perhaps my question should be rephrased as
"What effects (if any) do not cross planar connections?" ?)

What effects can apply to a creature inside a Portable Hole, from outside?

If a kobold is standing just inside the edge of a Portable Hole,
& is therefore on another plane, what effects (if any) can touch it?

What effects (if any) can reach across the planar connection?

Example scenarios, for all of which the same question applies:

• Can a character standing in the adjacent space directly outside the Portable Hole, use a weapon's Reach to hit the kobold with a Melee Weapon Attack?

• Can a character standing in the adjacent space directly outside the Portable Hole, hit the kobold with a Melee Spell Attack by casting Inflict Wounds with a range of Touch?

• Can a character standing in the adjacent space directly outside the Portable Hole, hit the kobold with a Melee Spell Attack by casting Vampiric Touch with a range of Self?

• Can a character standing 15 feet from the Portable Hole, target the kobold's space with Bones of the Earth's AoE, to pinch the kobold between the pillar & ceiling?

• Can a character standing 15 feet from the Portable Hole, hit the kobold with Fire Bolt as a Ranged Spell Attack?

• Can a character standing 15 feet from the Portable Hole, target the kobold's space with Flame Strike's AoE?

• Can a character standing 15 feet from the Portable Hole, target the space adjacent to the kobold which is just outside the Portable Hole, and hit the kobold with Flame Strike's AoE?

• Can a character standing 30 feet from the Portable Hole, hit the kobold's space with Fireball's AoE?

• Can a character standing 30 feet from the Portable Hole, target the space adjacent to the kobold which is just outside the Portable Hole, and hit the kobold with Fireball's AoE?

• Can a character standing 30 feet from the Portable Hole, use the spell Far Step to teleport into the Portable Hole, within reach to hit the kobold with a Melee Weapon Attack?

• Can a character standing 15 feet from the Portable Hole, hit the kobold with an arrow from a Bow?

• Can a character standing 15 feet from the Portable Hole, throw an Alchemist's Fire (flask) into the kobold's space?

• Can a character standing 15 feet from the Portable Hole, cast Spiritual Weapon on a space inside the Portable Hole & adjacent to the kobold's space, to hit the kobold with a Melee Spell Attack?

• Can a character standing 15 feet from the Portable Hole, use the Trickery domain Cleric's Invoke Duplicity feature to project an illusory duplicate inside the Portable Hole & adjacent to the kobold's space, then cast Spiritual Weapon to hit the kobold with a Melee Spell Attack?

• If a character casts Hallow while standing in the center of the Portable Hole, do the effects extend outside the hole; & if so, what if the hole is moved afterward?

• If a character casts Hallow while standing in a space directly adjacent to the Portable Hole, do the effects extend inside the hole; & if so, what if the hole is moved afterward?

In short, do all effects other than those limited to a single plane, apply across planar connection points? If not, which?