About homing and switches...

[routercnc]

Picking up on question E) in post one - you could use a Hall effect sensor but they need a magnet 🧲 on the moving part and are likely to attract steel chips and filings and become unreliable. Proximity sensors detect steel or aluminium so are a better option. Your other options include cheap small micro switches or chunky industrial ones.
Ideally have the detected object on the axis run past parallel to the face not up to it so a fault means the axis crashes into the hard end stop not the sensor.
Oh and welcome back Jazz 🍻!