You can't catch a Snivy in the wild, but you can transfer it from Black and White or take a chance and try to get one on the GTS
NO
Snivey evolves into Servine at Lv. 17.
ditto
36
Level 17.
FU**In SNIVEY
No, it is only in Pokemon Black/White/Black 2/White 2.
No,Ash's snivey wont evolve
First you need to be able to access the Daycare Centre which is on the route between Wellspring Cave and Straiton. Snivy is in the Field/Grass groups so there are large variety Pokemon it can breed with, especially with Ditto (which 99% of Pokemon can breed with the exclusions being Legendaries and Nidoqueen)
The only way to find a Snivy is to get it from the starter Pokemon. If not, then you'll have to get it over the Global Trade.
You can't, you have to choose it as your starter. this is the same for Tepig and Oshawatt.
Go to Route 5