Usage patterns
仮に〈事〉としてもeven supposing that ~
Even if he were the culprit, he can't be convicted without evidence.
仮に〈人〉に〈事〉を任せるto temporarily entrust someone with something
We decided to temporarily entrust him with the manager's duties.
仮に〈事〉としたらsupposing that ~ were the case
Supposing that story is true, it would be a huge problem.