6* for Event?

First off I'm f2p, so I don't have many mons, But currently at max 5* Lulu, Dagora, Ramagos, Lapis, Roaq, Elucia, Belladeon, and Konamiya. For the evolution event I'll need to 6* 2 of these, I have no other 5* mons yet.

Any advice on which are worth 6ing?

I always here good thins about bella so she'd probably be one, but not sure about the other.

Thanks guys.