I got a puncture 140 miles from home on the M5. Very glad for the spacesaver.
Not so good when you pothole two tyres at once!
Fortunately a good friend lived not too far away who has the same model of car (Ford Edge) who lent me his.
Note: do not fit 2 spacesavers on the same side of the car. It...
Looks like M5 to me, it's over 4mm. M5 screws will normally be slightly less than 5mm OD.
https://www.trfastenings.com/products/catalogue/screws-and-bolts/Machine-Screws/Pan-Head/Cross-Recess-H-Drive/TR00009579-100
You need to take a (L & N) feed from the lighting circuit to either the switch position or you new light position, and then a cable from the switch to the light.
You can't just use the wires you have there already.
I stand to be corrected, but I don't think so.
Also, you may require deeper back boxes for usb ones.
If you are thinking of charging phones etc. then the original chargers are generally faster.
As pretty much all lights these days are LED, there isn't any need to use 1.5mm², 1.0mm² is ample (and cheaper). Add up the load and see. If looking to use smart switches, fit 35mm deep boxes to allow plenty of room for them.