like ur theory and how u support it but there also evidence to show its not shisui and fugaku or S06P
Danzo has Shisui's eyes so he must've found his body
Fugaku was killed Itachi and everyone saw it
Sasuke's mom would've noticed0_0
Tobi might be Fugaku cuz remember Itachi was alone!... at home when 9 tails attacked
that's the only evidence i would beleive that tobi is Sasuke's dad