Pick your own starter #pokemon! Here are the rules (that I made up, who cares, do your own thing if you wanna):
1) must evolve twice
2) must not evolve using special conditions (friendship, stones, locations, etc)
3) (I don’t think there are many legendaries that evolve twice anyway but) no legendaries
Does the trainer choose the Pokémon, or vice versa?
There aren't a ton of pokemon that evolve twice and don't evolve using trades or stones in gen I and II.
But Shinx is my answer.
If trading isn't an issue, then Abra, or Ghastly.
If OP isn't an issue then Dratini.
I could have a party that was just those four and a pichu and a mareep and I'd be pretty happy.