Unfortunately I don't know much about hypertrophy training, so I may be wrong with a few of the things I'm about to say.

I think that yes, higher reps at lower weight in the 8-12 rep range will generally target hypertrophy more than strength. You wouldn't necessarily want to do a strength program with higher reps to build hypertrophy however, as things like recovery will differ at higher ranges. I want to say that there would be diminishing returns fast if you only did compound exercises at high rep ranges.

I also see many hypertrophy programs will incorporate more exercises which isolate muscles at higher rep ranges than strength programs. I'm sure that this has to do with recovery, since you'll often see split programs like PPL (push pull legs) which offer more days in the gym split up between different muscle groups.

Not really

Because those exercises are "not made" for hypertrophy. Of course they will cause some hypertrophy due to the natural process of overcompensation

But a lifting regime like that is a bit apart from a hypertrophy program which usually involves more isolated exercises

(btw 5x5 means 5 sets of 5 reps each, so if you try to replace that with 12 reps you're taking the program in another direction)

It depends on what you find more adaptable, really.