MTG Salvation

They get the buff as a cast trigger and then the spell would resolve making them 4/4 dragons without the buffs. just as if you cast giant growth on them before playing the dragon spell they would revert to 4/4 flyers. Either way it would be bad even if it did work the way you wanted.

Against Aggro your plan is to stall with cards like Mizzium Mortars, Abrupt Decay, and Dreadbore until you can play your Thragtusks and Huntmaster of the Fells. Although it pains me to say it, Bonfire of the Damned is really starting to get marginalized. Yes it is a great card when you miracle it, but Mizzium Mortars can act as a sweeper as well as a single targeted removal spell. Also Mortars can't be countered like Bonfire can with Frontline Medics Ability.

When it comes to junk reanimator, you're going into this game knowing it's a bad matchup. Alot of your cards are pretty dead in this matchup. There are a few cards you can play that can help. Deathrite Shaman, as was mentioned before is a great card in this matchup. Not only can it remove there guys but when they play cards like Grisly Salvage, this puts lands into there yard so he also becomes a mana dork. Another overlooked card is Curse of Deaths hold. This card kills Lingering Souls tokens, mana dorks, and makes any Lotleth Troll in there hand a dead card. The only answer Junk Reanimator plays to Curse is Acidic Slime. But just resolving it for a turn would probably sweep there board of a bunch of cards. When they have no mana dorks or tokens, Craterhoof Behemoth gets a lot worse. Also Curse is great against aggro if you can power it out on turn 3 or 4.

Hope this helps!

Edit: Also Ground Seal And Cremate are not cards that should be overlooked.