Oh, I'm full on immersion, I don't even consider playing without tabletop audio on. A hounted house without candles and creepy music? No way!
Scrolls will work how I need them to work, regardless of the official 5e rules. I think I'll let the artificer have ritual casting and use any magic item, that's kinda their thing and 5e does a lousy job with them imho.
I have read the whole module for pathfinder and know the "Island at the..." adventure by heart. Also, I prepared some handouts with all the characters my party should know of and have an A3 format map of both the continent and of Flint already printed out.
When it comes to accents, it's not my strong suit but I always incorporate them in my games and this should be no different. Teiflings will be French, the Clergy mobster Italian, Drakrans shall be German, and Risuri will propably be a mix of english accents. I have no idea what to do with Ber and Elfaivar. Only other accents I'm comfortable pulling of are Russian and Ozzie and I can hardly imagine elves as Russians, even harder to imagine them as Ozzies when we figure in where they stand contextually in the campaign.
I'm really glad that the player with the most common sense in my party decided to be a skyseer, I'm sure she wont gaze into the stars at every given moment and will surely be satisfied with rather cryptic answers. On the other hand the spirit medium paladin I could see having trouble with. Not so much because of the player, the power to speak with the dead could pose trouble in an investigation based module.