This is all amazing stuff, but I have a request. Is it possible to add the IPA for the examples?

Like for example, with "sj sja[h]s" (vengeance), i'm guessing it's pronounced as [st͡ʃʰas] ?

Or from you description of "ft fta[h]r" (after/later), can i assume it's pronounced as [fθaʰɺ] ? Also, since you didn't really mention, I assume the "r" is an approximant, as having an aspirated [a] followed by a schwa wouldn't really make any sense.

Also from your description of "y dy[h]r" (differ/different), I assume the "y" is a palatal approximant, and since you mentioned it ending into a long vowel, the "r" would more of a schwa rather than a alveolar approximant. So I assume it sounds something close like this, [djʰə].