Which Poké should I Invest In?

I’ve got two Rookidees and I’m choosing between them on which to fully invest my candy in. I’m leaning towards boosting the 373 simply for its higher IV’s and base CP.

My primary concern is the 362 Rookidee being an XXL — is there ANY reason why it’d be better or worse to invest in it over the higher IV 373 Rookidee.

Another thought is are there ever showcases based on 3rd stage or later evolutions of Pokémon, or is it by and large only first stages/heavily spawning Pokémon?

Thanks for any advice!