Secondly, I'd also like to reduce the AP cost for going into Sneak mode in order to counteract the sneak nerf. I haven't yet found the way to do this.
Hard-coded. The best you can do is script in bonuses to counter the nerf such as the mod scales did:
http://www.nexusmods.com/divinityoriginalsin/mods/68/?Still requires the full 5 AP to enter sneak mode in combat before one could counter anything. It's really hard to think of a reasonable 'counter'.
All crafting recipes from classic, where gear could be boosted with Sneaking are still in EE, i.e. Crafting was never adjusted, as also the wrong and missing scroll recipes tell.
(body, garment, belt, gloves and helmets can be boosted with sneaking, garments had their INT requirement back then, but it was possible to increase sneaking by 4 with void essences back then, with enough int, no point was required ...)
Might be a better idea to 'fix' Walk in Shadows, which somehow must do a saving throw against itself when used, because the 100% chance with Dex 8 still lead to failure often enough ;-)
Says nothing in the log though ...
