#1 - yes, basically make a Y cable with Power/Gnd at the end of the Y legs:
P------|------------------P
G____|___________G
| |----------------- P
|______________G
#2 - each transistor needs to have
Continuous Collector Current:
of 10 * LED current (10 X 0.02A = 0.2A, 200mA)
The 2n2222 can do that. The other2 can't.
Good to give yourself some margin there too - don't run parts right at the limit of what they can do.