which in jail is more like swallow her keys since she always loses her keys. that's the only thing leo did. Get keys, return them to Lucy (and the other girl). Nothing more, nothing less. For the rest Lucy actually fought by picking some decent spirit(s).
Yes, and thats why im saying Leo saved Lucy, she didnt solve that issue on her own like a lot of people have been claiming.

I don't know, that seemed more like an exception than the norm. Like usually Loke would take up Lucy's magic but he clarifies that since he is specifically fighting against Lucy that for the exam he wouldn't take up her magic and instead sustain himself with his own magic.
To me it soundet more like he was clarifying that when he crossed over on his own, then it would be his own magic he were drawing upon.