A minor fender bender knocked the pass side frt flare and fender splash guard off shearing all the fasteners. What do I need in order to re-fit them? Later, I will need to replace the front bumper cover - is there such a thing as a how-to instruction pamphlet covering these sort of body repairs?

Minor fender bender ? Where , front , rear etc.... Could have damaged wiring harness , sometimes GM mounts the PCM - engine computer behind fenders , body parts etc...

this may be due to the battery check that whether it is in good condition

a rivet is a permanent fix as in a pop rivet and is not easily removed once fitted
a clip can be a metal "u" piece that goes over the edge of the guard and a screw then is ******* into it through a drilled hole in the guard
( like a nut held in place)
or it can be a plastic fastener that fits in a predrilled hole and then holds the flare in place by another section that pushes into the plastic and expands that section to hold it all together
I suggest that you go to a panel repair shop and talk with them to see the differences and the best way of fixing the flares as they have to work with that idea all the time

Unfortunately, your vehicle may not really appreciate your efforts!
The splash guards are normally installed on the folded edge of the fender well.
Depending on the material your fenders are made of, they may tear off very quickly. :-(
To reinforce the screws, small metal washers may help.
You have not indicated whether these guards will be on the front or rear fenders, or whether you are using the super heavy duty ones that fit only the rear, and hang under the back of the vehicle.
God bless your efforts.

9 times out of ten you half to replac them even if was a minor fender bender. The seat belt reel has a component the breaks and locks under a certain amount of load.

Vw's are a bit complicated. Generally though, there are up to 5 Torx T25 screws in the wheel splash guard just behind the bumper. There might be one hidden up near the corner what the bumper corner meets the fender. Down by the fog light covers (usually behind it) are more torx screws. Underneath the bumper are about 4 more torx screws, but these are often machine threads like bolts. You will need to probably find the few screws holding the top of the grille in and remove them also as there are two torx bolts behind the corners of the grille. The bumper should note be able to slide of the guides below the fenders. Good luck and be careful when yanking and prying on plastic parts.

They don't make diagrams for brake lines. The lines are sold in bulk. You need to measure and duplicate the bends in the orignal lines and cut/flare the lines yourself. You will need a tubing cutter, flare tool and tubing bender.

should be a fuel cut off switch on drivers floor on door side.

inertia switch

ford has a fuel cut off switch in case of a fender bender sometimes located in trunk or by pass floor board need to reset switch