Ben

The funny thing is that for some reason the pentalobe bits seem to let the screw nut go out and screw back in.

If you have isopropyl alcohol on hand. You can use it to help weaken the adhesive temporarily when lifting up the adhered home button.

Yep, clean the old adhesive and apply some Tesa 4695 or 61395.

I honestly do not understand why the back cover is removed from the mid frame, you can remove the mid frame silver plastic with the back cover anyway.

They can’t be both PMI8994 Power Management IC’s I’ve looked at them under an microscope and one is PMI8994 and the other is PM8994.

Check step 3 of this guide: Microsoft Surface Pro 5 Screen Replacement

Unfortunately the connector plugs are different and the cables go in different areas.

No. Different connectors.

I would call that a grounding plate as it looks like it provides grounding for the power button assembly to the board. Without ground the power button would not be able to send current pulses when you short the power button by pushing it from the power button itself > power button cable to logic board.

Not sure why they did this because they could of just provided ground on the cable itself. That's my understanding because that put should not of been designed like that.

The thickness / coverage of the area available to put the adhesive is plentiful which allows you to use more adhesive than you need. Anyway what I use is red double sided tape as it's adhesive strength is very good and the thickness is good to use in this case. It's called 'PET red double sided transparent tape'.

I think iFixit sells rolls of them which aren't really expensive at all.