4x Rose!? I'm shocked...

All the 4* are worth leveling up to fill out your team unless you somehow have a ton of 5*.

For 3* I prefer the ones with high speed since that is the one stat where even 2*s can beat 6*s. HP more important than def because 3* def doesn't get high enough to matter. Rose Diana and Marigold are good ones.

I mostly level the ones I think are cute though, they will be replaced eventually anyway. So most important is the look of the evolved form