Depends on the mod in question. The guide is built with no file conflicts in mind but if you start adding your own mods in you will be responsible for dealing with any potential conflicts meaning if you end up breaking your game then you are responsible for fixing it, not me. If you deviate from the guide too much I won't provide support.
It is not essential however I do still recommend all the mods present in the guide
As long as your system can run vanilla Cyberpunk 2077 at a stable fps then you should be fine as generally speaking the fps impact from these mods is small
The guide is built around manual installation however if you wish to use a manager then you're welcome to. Just keep in mind again that I won't be able to provide much assistance since I don't use a manager myself for this game
As long as you provide details I should be able to assist. Do keep in mind however that Cyberpunk still has some bugs here and there so make sure that if you run into a bug, confirm its just a vanilla problem for now and not a mod problem
I am open to suggestions but do be considerate before posting your comments. I am trying to preserve the original game to an extent. Also, make sure to check that whatever mod(s) you suggest still works on the latest version of the game