Talents trained in the test realm using pets that were already hatched in live realm are true indications of what talents you'll get if you train them in live realm. Pet Hatching in test realm is nothing though because it's random. Talents are determined at random upon hatching, so the pets you train to higher levels in test that are real pets have those talents already. Pets hatched in test will have different random sets, just like doing multiple hatches with the same 2 pets will end up different each time.
Things that exist in live realm before test opens go to test, but things that happen during test do not go back to live. So whatever pets, gear, or other items you usually have, you will have when test opens. Your pet will have the same talents in normally does, and if you train it, it will unlock the same talent it would on live. But if you hatch a new pet, buy something, or get a drop on test it will NOT exist on live. If you hatch two pets on test, and hatch the same two on live the offspring could be different, and get different talents.
Well, transfer of stuff is ome-way from live to test, BUT a pet created in the live realm will have the talents it manifests already decided, so if you get Spell-Proof at teen on the test realm, the same pet will get Spell-Proof at teen in the live realm.