Great questions. XD I don’t really have any tips for writing in first person (tho I tend to like that POV), so I’ll skip that question.
As for the other… I say go for it. Having interludes in the middle of the story in a different POV/tense would be pretty jarring, but if you had an epilogue/prologue in a different POV/tense, it would definitely bring attention to those. 🙂
