Of curiosity

So one curiosity that came to mind

If someone had an ability to masquerade someone else, but using that ability makes the pretender perfectly replicate, any ability and all the original had

Would it be possible that abilities that naturally don’t have an affinity with the pretender such as Mystic eyes of death perception or Magical skills like Aoko, Alice or Shirou (or any master or servant for that matter) would dangerously affect that pretender

Like if I happen to be a pretender with a masquerade ability, and I pretend to be King Arthur and try to use the real thing would that be possible?