Depends where he starts. It probably won't take him more than a couple of months, and he won't bulk much if at all if he's not eating for it. As I've already pointed out, that's why gymnasts don't look like bodybuilders.
2) Let's forget about the above and say, for argument's sake, that the range is 8 to 12 reps.
Let's also say, for argument's sake, that Q currently fails at 8 reps of each of the "harder bodyweight exercises" you're recommended.
How long do you think it'd take him to get to 13 reps? Because that time period is the time period he's spent in our (arbitrary) sarcoplasmic hypertrophy range.
You've misunderstood the sarcoplasmic hypertrophy range. It doesn't extend on forever. There comes a point of adaptation where the body stops packing extra sarcoplasm around the muscle fibres and adds new circulatory capacity to remove waste products faster.
Honestly, there's only one word I'd change from your first post in this thread. Switch "for high reps" to "for low reps", and it's entirely reasonable.