Which to buddy?
Snorlax (current buddy) 2284CP, Lv 24.5. 15/8/8 IV
Zen+Body Slam
Dragonite 2347 CP, Lv 21 (15/15/14 IV) Steel Wing/Dragon Claw
Chansey, 911CP, Lv22 (15/11/13 IV) (Now only at 16 Candy, want to make a blissey)
I'm thinking of completing the Snorlax first (until at least Lv30), then the Dragonite, then Chansey. What do you think?
Answers
I would say this answer depends on biome. In desert biome, for example, you can find Chansey much easier than Dratini - which is basically nonexistent.
I would go with the Snorlax first, finish that off. Then go with whichever is the more difficult to locate in the wild between Chansey and Dratini. I'd probably buddy with Chansey.
TL;DR - get your 'lax high enough to stay in a gym, then switch -- 'nite if you need attackers, Chancey if you need the best Defender!
I was in your situation too, but my Snorlax didn't have ideal moveset like yours ... still, I only needed him at level 26 to be on gym duty for over a month - letting me walk Chancey (I didn't even see 1 during Valentines :-(
YMMV, depending on your gym meta - stable suburban here.