E-ing a Mongoose Fireball

Hi Folks,
I have a Mongoose Fireball as a donor bike for a project build and have a question about fitting a BBSHD. The bottom bracket has a chain guide mount welded around the chainring side. I assume I need to grind this puppy off in order for the Bafang to fit?

https://photos.app.goo.gl/g2MiohhJD22A9w8VA

Is that a mount for an e-type front drailer, or just a chain guide?

Just a chain guide. There’s no front gears on it.

Since searching the internet is utterly broken these days I'm having trouble figuring out how to get 20 inch wheels on this thing. BMX wheels have a different axle size and some have a threaded freewheel. Axle width obviously isn't long enough for a MTB frame so are the hub's compatible in that I can swap my axle's over in order to fit my 8 speed cassette? Or am I better off sourcing some 20 inch folding bike wheels that have a cassette support built in. These seem very hard to get from anywhere other than china/ebay.

Note I'm very aware of the impacts of a 20inch on this frame (gear ratio, torque, clearance height etc).