You've just edited the current mobs to add a little bit extra. If you want new beast monsters make them new. :\
2nd mob was original (apart from the name) for beasts...if not considering other forums posts that have introduced the idea of a bat. I think someone pointed out that no-one needs another Greaver and a flying mob should avoid being bat-like. Giving speed up is nice for a new mob and all, but beasts already have an attack up mob. If any family needs a booster (as in it gives power ups) mob then it's Jelly/Slime.
My idea for the flying mob;
- The mob would be a bird (all feathery and flying and stuffs). It would circle the player in groups (Wolver pack size) and launch strafe runs (fly past the player, hitting once) every few seconds.
Of course this is your thread, so rather than my above not-thought-too-much-about-idea I'd rather see you evolve your idea through your own ideas. :D
Spike shooting beasts are a cool idea but spikes, outside of snarby, are Jelly/Slime monsters and it'd maybe take away from them...I dunno...I feel I will be disagreed with on that point.

@Fangel

Well the spikes wasn't really an important point to me. Your point makes sense.

My view on why Beasts are so weak : every attack they have is a charge attack.
Alphas should get something like a quick bite that only hits once but doesn't give much time to block (other advanced mobs such as Mecha Knights that have these attacks seem to work pretty well in the CW and not be OP).

For a charge attack though, the Alpha Wolver isn't THAT bad of an advanced mob. It's pretty much unblockable.