Regarding your question on editing how a Pokémon evolves, I recommend using YAPE - Yet Another Pokémon Editor, to edit the evolution trees of Pokémon (amongst other data). You can find YAPE in the Toolbox section of the Emulation forum, and there is a tutorial on using YAPE in the Tutorials section - if you can't find it, use the Search function.
Either way, welcome to PokéCommunity, I hope you enjoy your stay here! :3
Either way, welcome to PokéCommunity, I hope you enjoy your stay here! :3