1) I heard that the anouncement for Sonic Adventure 3 was really a remake of SA1, if so then when will it be released and what systems will it be on? 2)Are there new characters in Sonic Advance 2? 3) What is Ristar like ( I heard it was going to be on Sonic Mega Collection)?
1) Dunno the date of release, but it's on GameCube like SA2 Battle.
2) Refer to the news page.
3) Ristar is like Sonic, only you play as a little star guy who can grab enemies and bonk his head on 'em to take 'em out.

~ SA Tails