AF THE BOSS

Hexadermal ASCII code
lol just translate it and you'd get "enrichan"

Secluded meadow is at the side of route 3XX. Idk where but to give more info, go to the end of sylen city, where a new route awaits, now go to the very right of that route, you should see some water, use the boat to follow the water upwards, and then you will find it.

Rainbow Quest?

Talk to the guy inside your house (seaside vista)
then Find willie and hessa in secluded meadow

Im sorry, but you can't ''catch'' W.T, you can only get the Rainbow Forme of W.t which is the Egg from the rainbow quest

Hm?
What do you need?

card prism tower and beating stocha is left