replace character during the game

I want to make a button to replace my character on the scene with another character not on my scene during the game and I founded a two ways to make that on tutorials
1- get character from other scene
2-get character from other layer

but I want to know are there any other ways to doing that ?

and are the characters polygons that’s not appears on my scene will effect the game process time speed or will’t ?

game objects on hidden layers shouldnt affect rendering time, unless they are lights.

the replace mesh should work, but there are a lot of other things to consider. managing inventory, stat changes (will one character move faster, jump higher?), and keeping track of health.

what i do is import a file with meshes, each mesh has vertex groups. the meshes are in a diferent layer, and so it works as if they where in the same file from the begining. you can have diferent files with the meshes you need in the scene, materials and textures are imported, the only thing that should be in the main file is the armatures and logic.
you can have as many meshes as you need, they do not affect performance, as long as they are not seen.