Perhaps ALL of the characters could at least be related somehow? That would limit choice of races, but I could see Eladrin having distant Elf cousins, and Half-Eladrin could be handled mechanically the same as Half-Elf. Having a half- would allow one or more Humans to be stuck onto the family tree, and the Human(s) could have short kinfolks who'd be Halflings or Gnomes for game mechanics purposes. Anyway, just a weird thought. But if everybody did want to do it, it'd be easiest to stick with Eladrin, Elves, Half-Elves, and Humans, plus maybe a more exotic fey from the Monster Manual, a la Tarrk? [For those who don't know, Shayuri, Tarrk was Walking Dad's Minotaur Barbarian in the first 4E game that I ever ran.]
"Point Buy" is a 3.5/Pathfinder concept. [Well, not really....] 4E has the more limited choices of A) Rolling, B) Standard Array (16,14,13,12,11,10), or C) B*stard Point-Buy with 22 points to add to fixed starting numbers (10,10,10,10,10,8)*. Personally, I like the Standard Array, but if somebody prefers to do Option C) that would be ok, too. Just for giggles, let's try NOT to just have totally random rolls for scores, ok?
[sblock=* B*STARD POINT-BUY COSTS]
09 : -(1) [costs 1 to make the 8 a 9, costs -1 to make a 10 a 9, or that's my reading of it anyway]
10 : 0 (2) [costs 2 to make the 8 a 10, then you can raise it normally from 10]
11 : 1
12 : 2
13 : 3
14 : 5
15 : 7
16 : 9
17 :12
18 :16
[/sblock]