The ich will mostlikely come back. It is almost always in the tank. I am dealing with ich right now and want it gone for good. The only way to do that is to QT your fish and leave your display fishless. Ich's cycle last 30 days but I would wait a lot longer then that, 60 might be a bit much. Copper may work with ich but hypo is safer.
I was reluctant about doing hypo, but now I have my 55g QT tank with 3 angels in it and the SG is about 1.010. So far it definitely has slowed the ich down. Ich can't really survive at this low SG and some will actually explode. Also the low SG puts less stress on your fish, since there is less salt for them to filter out. Therefore, your fish are stronger to fight of ich and leaving it without a host, thus killing it. Hopefully for good, but ich is a stubborn parasite, the longer the wait, the better.
Always QT every fish before adding to the display, may be a pain in the *** now, but you'll be thankful later. Also, PBT are notorious for getting sick, they need special care and lots of attention. Good luck, keep us updated.