The good news is that figs will almost always come back after being cut to the ground.
Or an oxeye daisy (Leucanthemum.)
Yep, unfortunately. (Well, the C shaped ones.)
The other long grub I don't recognize.
Yep, 4 petals is right I think so either an invading flower there or it's something else entirely. Leaves look at bit like a Leucanthemum?
Prunus are pretty bomb-proof as far as trees go so I wouldn't bother treating the roots with anything.
I think it'll be fine but I wouldn't pull any more stems this year to give it the best chance of building the crown up again.
If it has been there a few years it'll recover. If it's a newly planted one it might struggle.
Good point nut.
Might be some kind of Evening primrose but doesn't look quite right. Have a sniff of the flower - Oenothera are fragrant late in the day.
Some are self-pollinating to a degree but crops are much higher with cross-pollination (like many fruit trees and bushes)