On 3, there are two solutions I know of, and both can be used at the same time.

One option is to use some 'external toothed lock washers' on the pot shaft pointing upwards. These are washers with serrated edges that dig into the wood and help stop the pot rotating once some pressure is applied through doing up the nut on the top surface. You'll need to attach them to the pot to stop them falling off when you fit the pot through the F-hole (as with any washer on a pot that's going inside a hollow guitar, and I use a light general-purpose glue you can find in any stationers. Being a spring type washer, it also helps stop the pots working loose in the future.

The other is to ignore the advice in the link above, use a template to get the positions of the volume and tone pot right, then make a wiring harness using stiff wires with the pots facing each other. The easiest thing here is to replace the kit capacitor with a Sprague Orange Drop of the same value, which has nice long stiff legs which will help keep the two pots facing each other. You can also link the back of the two pots together with a piece of thicker solid wire. If you run any other wires between the two pots, you can tape them up to form an even more solid link. So when you pull the two pots through and tighten the external nuts, there's a lot of initial resistance to the pots turning, allowing you to easily do up the nuts finger tight,

You can obviously employ both methods together, but even without either of them, you'll probably find that once the nuts are on hand tight, there's enough resistance there to stop the pot turning when you use a spanner. You should also be able to get a finger through the F-hole to stop at least the volume pot from turning; a second pair of (thin fingered) hands is useful here.

The output jack can be another problem area, and a glued-on toothed lock washer is also useful here. On my ES-3 build, I've opted for an easier solution so have widened the jack hole out and have bought a Les Paul style jack-plate, so that I can simply pass the jack socket through from the inside, connect the socket to the plate nice and tightly whilst on the outside of the guitar body, then screw the plate on to the guitar.

I have bought an Allparts device that's supposed to allow you to screw jacks sockets on tight from the outside. It's got a central rubber finger which is supposed to jam in the hole, allowing you to then slide down a plastic box spanner which you turn to tighten the nut. But it's not that great. It might make the middle bit easier of doing up the nut once you've got the nut on the thread, but it doesn't get the nut on that tight IMO (no leverage on the round spanner part), so you need to revert to a normal spanner right at the very end.