Your on the right track with strangle root giest. I would put in some more undying to trigger your evolve abilities more often, plus its better against hardcore removal.
Probably replace your bloodrush and the Occulus and put in that third strangleroot giest, and young wolf, and even the Vorapedes.
Clones would be good, too. You can copy an undying creature, then when it dies you can have it come back as something else.
The problem with that strategy is that your Master Biomancers will shut your undying down. So, if you do that, take the Master Biomancers out. I honestly thing it would be worth it.