今日は建具替えといって、屋形のふすまや障子を夏物に替える日です。
This comes from a subtitle from 舞妓さんちのまかないさん on Netflix. What is the significance of といって here?
Literally, I would have thought 'called', but 建具替え means literally what it is. So my current interpretation is just that it is adding more information, something like 'that is'.
Today we are changing the fittings, that is to say, we are changing the fusuma and shouji in the house for the summer ones.
You are close. As you guessed と言って literally means "called." Based on your translation, it seems like you got the order reversed. Xと言って means "called X." I modified your translation to capture the overall meaning of the sentence:
Today is the day when we change the fusuma and shoji in the house for the summer ones, this activity is called 建具替え.
It might help if you consider それを omitted like the following:
今日はそれを建具替えといって、屋形のふすまや障子を夏物に替える日です。
Hope it helps!
いって is the connective form of [言]{い}う, to say; and と here is the quotative と applied to the previous part of the sentence.
In effect, it does mean "called", or perhaps "so-called"; but it modifies what comes before. If I'm thinking straight, the entire clause 建具替えといって then adverbially modifies 替える.
I would render it: "Today is the day of the so-called 'fitting change', when we swap the house's fusuma and shouji for the summer ones".
