Agree. Converting salary to bonus is borrowing against future cap space.
As for this:
20M signing bonus
42M total guaranteed roster bonuses
62M guarantees between the two types of bonuses
those roster bonuses are NOT guaranteed if you aren't on the roster. Usually it's paid on the first day of the new season in March (or third or some other early day in the new season) and all it does is make sure that player gets that money if they get cut. It's effectively guaranteed salary.