Welcome to the forum.
I cannot tell you about the focus peaking history on the XE series, but from my experience with other bodies, it gets better with each newer body.
As far as lenses go, keeping in mind your thoughts regarding your budget:
Used Fujifilm lenses are usually really good, they can be operated in manual mode as well as in auto focus mode. Your local camera store may have some you can try, if not, there are plenty of online stores that sell them. Some stores sell them with a xx-day warranty so that you do not get a bad copy.
Rokinon (Samyang) and Viltrox make some great mf lenses for x-mount cameras, you can get these directly from them or from resellers.
https://rokinon.com/collections/fuji-x
https://viltroxstore.com/collections/x-mount
Editing software will depend on which computer platform you have, Linux, Mac, Windows or “other”. Free or low cost editors include programs such as GIMP, Affinity Photo, Pixelmator, etc. You may want dedicated raw converters such as RawTherapee or DarkTable or Fujifilm’s Raw Converter (Silky Pix). Adobe has a line of subscription based editors that you may like.