Does the contest stats remain in Firered and Leafgreen?

Question

For example I max out the beauty of a feebas in ruby/sapphire/emerald and trade it to firered. If I level up the feebas in firered, will it evolve?

Answer 1

Yes it will. I tried it on my LeafGreen copy using a Feebas I traded from Emerald with a high enough Beauty stat for it to evolve. Leve it up and you'll get a Milotic in front of your eyes.
Source: Experience