User blog comment:Water Dragon Slayer/DREAM BATTLE CHRONICLES: FIRST MATCH!/@comment-15382134-20130716225329/@comment-7418318-20130716232925

The problem is that each spirit exists only once.

Even with Gemini turning into Lucy, Loke can only be summoned by one or the other. It's impossible to have 2 Lokes (unless Gemini turn themselfs into another Loke).