I could suggest you to try to do it first, if you do a good scene structure, should be easy to replace the problematic parts.
On mobile, the first problem you can get may be related to overlap/collision detection but that can be reduced by visibility enablers or techniques like the shower of bullets demo.
Look, this is the platformer demo on my horrible smartphone, still playable on this state (remember all these are animated rigid bodies):
Of course texture size can affect the performance but that is easilly solved by scaling down, you won't need 4k textures for a 32x32 sprite zoomed 0.5x on a small screen.
And better open another post for the rest of the questions not related to the title.