Link's Clawshot is too long of a range for a psychokinetic grab imo, i think maybe Toon Link's grab range would be better, as its still ranged, just shorter.
As for speed, Silver is the slowest character (in 06') on the ground, so he should be around the same speed as maybe Mario, or Ike, or something like that. Air speed should be slightly faster. Give his first jump the same height as Luigi's, and the midair jump the same height as Mario's.
His up special should give around the same distance as Fox's. He should also have high traction (being the slowest hedgehog on the ground). Fall speed should be around Wario's i think. And his weight should be slightly higher than Sonic's.
wasnt silver only in one game?
As for playable in a main series game, yes. For appearances (playable or otherwise), no.
As far as i know, Silver is playable in these games:
Sonic 06'
Sonic Riders Zero Gravity
Sonic Free Riders
Sonic Rivals
Sonic Rivals 2
There may be more than that but other than the last two on that list, i know he's playable in all of those. Other than those though, Silver appears in other games just not as playable (such as in Sonic Generations as a Boss)