itch.io

Just load the main.chr into an editor of your choise( e.g. Screen tool) and edit it.  Note, the same character graphics are duplicated in other tilesets, so you will have to change them as well.

Oh, it is loaded allright, perhaps you have looked only in one file, it's not in game.asm

The last one is correct.

On second thought, if you are modifying the code from the episode 5, then, I believe, I was still using the mapper 0 back then, so the bank switching shouldn't be available.

Hey, where did you put that custom nametable?  Also perhaps you gave the nametable a different name, than it was hardcoded :)

Switching banks is simple, load bank number to a register y and call subroutine bankswitch_y.

Have you posted anything on Github? Since questions like this would be more fitting there.