out of the original 2 options: stronger base moves and ok base stats

from the current 3: Salamence is psuedo-legendary, they usually will beat most other none-psuedos with ease

totally :D

the problem is i don't know were you can catch one in pokemon black

to get Noctowl, go to the abundant shrine, I would guess at night due to being an owl

to get Galie, you'll have to send one from a genIV game

for salamance, he's white only unless you have dream world. if so you can get him at Rugged Mountains when you have over 10,000 dream points

All info taken from Serebii.net

White forest I think u could get a baton there

Actually I think it depends what type of Pokemon you have now and your basic needs now and I think it depends which one is easier to find as well because you have to find the Pokemon first in order to catch it.