On the mini, I use these settings for eSun PETG.
245 extruder
60 bed
45 part removal
2mm retraction
I didn’t get good layer adhesion at 225. You might try increasing the extruder temp to see if that helps with the jamming. You could have a blocked nozzle as well, but you replaced it recently. Did you tighten up all the screws? That could help with x/y issues.
I’m getting the best results with a 0.4mm first layer height, 0.1mm normal layers, at about 68% flow rate. Even after calibrating the extruder e-steps, I get significant over-extrusion. I’m working on getting taller normal layers, but I’m getting over-extrusion making vertical walls look crappy still with blobs/zits. There’s a guide from lulzbot about calibrating the e-steps. It might be worth a try to see if it’s off.
I’m using Simplify3D for most of my printing, with Cura mixed in a little here and there. I’ve never used Slicer, so I can’t say how well it works, but I would think it would be fine.
The other questions don’t really apply on the Mini, so I can’t say much there. Unless you have the PEI bed as well. For cleaning I usually just softly wipe with a scotch brite pad. Once in a while I use rubbing alcohol to clean any residues from plastics, hands, etc…