Definitely 6" figures - tell-tale signs:
1) Kylo Ren's Lightsaber - only the 6" version that came with the first 6" version released had that single-piece blade that can be removed from the hilt. The K-Mart Starkiller Base version featured a lightsaber with non-removeable blades, as does the smaller 3.75" version
2) the knees - specifically looking at the Poe figure - looks like the 6" knee design and not the "ball-pin-joint" style of the 3.75" figures.
That being said, there's no reason why the digital sculpts for many of the 6" figures couldn't be down-scaled to 3.75" - so I wouldn't be surprised if we did get that version of Poe, I also think we might get Finn in his Armor and Rey in the end-of-the-movie outfit as well - makes sense to get the three new main heroes in their two outfits from the movie...