sorry i dont know anything about them but i know alot about JAEJOONG:) lol

i think the two girls in snsd were stella (i think she was siwon's girlfriend) and the other girl is soyeon (she's in T-ARA now)

Well... For Super Junior, there's Henry and Zhou Mi, who are a part of the sub-group Super Junior - M. They technically weren't a part of the original group, but I've always counted them as 15. As for SNSD... I don't like them much, so I wouldn't know. I can only name the ones who are in it currently. I can name everyone in Super Junior, though, but that's because their my bias group.

hmm i knew two name who part of snsd before debut lee yeon hee,.,and stella kim who rumours as suju siwon gf..

Well, SNSD members weren't fix until like last minute. A lot were drop and then changed and then added, there was never a fix number of people in that band. So I'm guessing some haven't been added yet and some didn't debut. But they basically had to have a lot of members to be counterpart for SuJu.
But even SuJu was like that. Ryeowook didn't join until few months before debut. And Kyuhyun only join 6 months after they debuted.
But I have to say, Sooyoung didn't really change much.

not sure.

L-R UP: Tiffany, idk, idk [sunny could be either girl #2 or #3...but I'm just guessing], Taeyeon, Hyoyeon, Sooyoung

L-R DOWN: Yuri, Yoona, idk, Jessica, Seohyun

well, that's based on how I see it. not sure though :)

... they could be members who didn't debut with SNSD... and lol there's two of them (bottom left and right) who both look like Seohyun to me...