I've gotta be honest, I really don't like some of the changes you made.
I'm sad that you removed the waking him up choice that made me laugh so hard that I instantly pre-ordered. That just really popped to me and made the game stand out as unique. It seems less funny now in general, though maybe that's just my memory. A smaller issue is that the blinking pen was kind of distracting since it's so large and blue against all that pink.
Your artist is very talented and it's a matter of personal taste, but I kind of hate the new sprite. It's much less vibrant than the old one, but would still be pretty enough if not for the weird white nose... shadow? Highlight? It's distracting. I kept thinking it was my mouse cursor. His expressions are pretty much always gentle and kind, which is maybe on purpose? But with the color changes he just seems blander. Again, maybe that's on purpose since he's the base model. He went from feeling like an immature but harmless brat to feeling very big brotherly which feels strange in context of the game. When you say you're going to include the original sprites, do you mean they'll be useable in game? Or just that we can have the artwork to look at? I would obviously prefer to wait for the original CG artist.
As it is now, I wouldn't have pre-ordered this game. I would have noted it and probably checked it out again upon release, but I wouldn't have been particularly drawn to it. Normally I'd at least find some good changes to point out, but it's been too long since I played the original to remember details. I do appreciate all the hard work you've put into this. I really am sorry to be so negative, and I hope it was at least half as constructive as I tried to make it.