Answer 1

No you will never see it again
But you do have a very very low chance you find a Pokemon with identicle ivs natures ect
But as I said its a very low chance of finding a identicle pokemon
Edit: like tiger jay said (she reminded me ) if you release starters legends or fully evolved Pokemon that can not be found in the game obviously you won't be able to find them

Comments

Imagine trying to find an identicle spinda with identicle ivs nature ect plus spots with over 4billion spot combos :o

Answer 2

No, because if you release a charzard you wont be see see it in the wild because as you know you can't get starter pokemon in the wild (unless you use A-R)