Hero upgrade recommendations

In hero rush I am planning to upgrade one hero to epic to celestial. I do not have a hero on higher rank with Scan, blink or invisibility ability. I can upgrade only one hero from them. I am confused between Dragon, Raven, Cyclops, Aenie Stalker and Ghost. Can I have some suggestions please? P.S. I am not very quick with reflections and a bit slow mover. Thanks.