No problem dear, your question is very clear! We're happy for you to choose how memories are affected based on what you feel would be most interesting for you to play out, be that total memory loss, a sense of deja vu, or complete retention.

As for Shiro, once again we're happy for you to make the decision on what would feel best to play out. You have full permission to play out Shiro fighting the disease if you would like to, otherwise, we are also happy to go with "your current body doesn't have this".