Fluxfire will still be extremely strong for PvE after the nerf, so I don't think you'll go wrong with that. Tamers tend to be about mixing and matching to counter their pets, and not so much about building a synergistic team. Many trainers won't require strict counter-comping to beat, but there are certain brick walls that are very hard with non-ideal teams.
It looks like you're leveling Ghostly Skull, Strand Crawler, Chrominius, Lil' Tarecgosa, and Death Talon Whelpguard. The first two are great tanking pets and very strong for PvE, so those are great choices. The three dragons are also decent, but you might want to branch out a bit here. Lil' Tarecgosa and Chrominius are both pretty specialized anti-flyers, which you won't really need more than one of (except for one trainer in Northrend with 3 birds).
Among your other pets, I would definitely level Anubisath Idol, and consider Disgusting Oozeling. These are both very strong in general and will be useful against a wide range of tamers--Anubisath is already amazing at lvl 4, and Ooze becomes a self-healing dps machine at lvl 10 (and even better at lvl 20).
I also started out with a bunch of dragons, plus Magical Crawdad (similar to your dragons+Strand Crawler): I ended up having to go back and level an elemental for a couple Mechanical-heavy tamers (I chose Phoenix Hatchling, which you have--he worked well) and a frog for a couple Undead-heavy tamers. A breed 5 rabbit would probably work just as well, and would be useful against elementals too.