You can only pick one character. You are effectively asking to be able to use multiple non-original characters, albeit in a non-traditional way. I don't think it'd be cool for you to be able to just cherry-pick awesome characters - like, let's say Vision and Goku - and have their memories in your head, but then we also have a guy running around named Goku who has all the same memories.
I think letting you make up a bunch of ORIGINAL characters and use their memories is a pretty good compromise. In fact, in my opinion, it's the superior choice.
I don't know if it says anywhere specifically in the rules, which is something we'll need Greg or Alex to fix (I also couldn't find it), but I'm pretty certain that this is the standard for character creation in regards to non-originals.
Also, side note:
Bro, stop switchin so much.

