As for Last Mission, I'm okay with not getting it since it's not very fun anyway and I understand that localizing it would be a ton of effort.
I just hope that additional voiced content in KH2:FM (extra scenes with Xemnas, Saix, and Xigbar) and KH:BBS:FM (Aqua's secret chapter) gets voiced in the eventual KH 2.5 Remix, though I'd be surprised if it weren't; the entire KH series' voice cast seems to have a pretty active relationship with Squeenix, save for Billy Zane and whoever voiced Aerith in KH1.
Well they voiced previously text-only Days content, right? So hopefully it's likely that the extra stuff will be voiced too.