Actually, if you look close the system is completely stock until the outlets of the twin resonators. Look how precisely the parts fit in the space provided.
The aftermarket final mufflers are smaller than stock and you can clearly see the heatshielding is for larger mufflers than shown.
However you are very close. 2 pre-cats, 2 main cats, 2 silencers and 2 final mufflers... BUT... there is one more... the H-pipe which is actually more of a plenum. This both quiets the car and IMO actually looks to the engine like the tailpipe. IOW, the engine doesn't "see" anything past this H section.
So, the answer would be 9 (nine) muffling devices.
No reason why an aftermarket system wouldn't fit precisely? but happy to take your word for it that it's stock.....very nice work from Toyo indeed in that case.
I can't see that H-pipe helping flow and therefore would hurt power but there for noise control (to cancel a particular resonance i suspect) so no doubt does what it is supposed to.
