Well, to me the basic concept is pretty solid, I like the idea and I like the direction you want to take with it as it really does get my mystery solving brainwaves going (I love mysteries as well so you could probably say I'm slightly bias towards this idea).
Plus I love the ideas of characters from different games/whatever in different series meeting up because it always makes me wonder what would the reaction of 'insert character here' be like if they met 'insert another character' randomly and so forth.
It also feels like you've sat down and thought about this, not had a random idea pop up in your head and then immediately plan to go ahead with it. It sounds like you've put some real thought behind it, and that you've realised where some parts might cause some issues but have thought of ways to counteract it or straighten it out without causing a paradox or simply making it so because you wanna write it.
I'd honestly love to read it.
However I have one tiny issue with it (and feel free to block me and never talk to me again after this because I'm a heartless idiot that needs a good slap).
I feel like resurrection is kinda overdone and just a way for people to bring back their favourite characters without completely getting rid of the reason why they died in the first place. To me, its a simple plot idea, and within the realm of 'fanfiction' or whatever you wanna call it, it's just a way for a person to say 'Oh I loved his character but they died so boo... wait a minute, I can fix that'.
However saying that, its not always as bad as I think its gonna be. Sometimes it can be written really well and it can surprise me (not that I'm suggesting you would sorta just throw it in there as a last ditch effort or anything like that).
Now, I'ma let myself and my obnoxiously long post out, I promise.