Thinking of using Grubbs(or a spider of somekind?), Fluxfire, and trying to decide on my last member, Spawn of Onyxia/Celestial Dragon, or Lil' Ragnaros. Trying to figure out which, making my brain hurt. This is just my first team of 25 I'm using, I'll level more for diversity later ofc.
"This is just my first team of 25 I'm using, I'll level more for diversity later ofc." As stated in first post.
But yes, PvE for now.
If you plan to level by just killing/capturing wild pets, it'll take lot of time but you'll be fine I guess.
However as you level your pet you'll be able to get quests to fight against master pet trainer. Also some achievements unlock Pet Battle Dailies (http://www.wowhead.com/guide=1345). And you'll get much more xp when you fight against a master pet trainer (exp multiplier is at least 2.5) and imo going against them is the fastest way to reach lvl 25.
I'd definitely level one of your dragons, onyxian whelpling was one of my first level 25's and it's seen me through some tricky stuff, the heal they have is immensely powerful when used right. It's one of my teams staples! I would also reccomend levelling a snail, when you get further up to the Pandaren spirit tamers, a snail is a total must have for the hardest spirit tamer!