I like every thing you have said in response to my stupid questions; and I like your ideas but why do you think Kagami is Tobi? why would he be out to destroy everything when he fought for Konoha in the Second Ninja War? I would be interested to hear your theory...
Alright due to my theory being long here's a summary
Kagami is the son of Izuna Uchiha and was a part of Tobirama's extended war team
His motive is purely: familial dishonour, so he wanted to become the Hokage to restore the Uchiha's honour, most likely brainwashed by Izuna who Madara taught his ideals too
When they were about to be ambushed he suggested the idea of a decoy, knowning hiruzen to volunteer getting rid of the most likely next in line for Hokage
However Tobirama went instead, Hiruzen became Hokage which only increased his anger
Then he managed to fake his death, had one or two sons (Obito and possibly Shisui ?)
While this happened Madara explained his eye of the moon plan to Tobi, entrusted him with his newly awakened Rinnegan while he was on his death bed and told him to find someone with a strong life force (Nagato's name was in the prophecy ?) so that he can use Rinne of Rebirth to revive him
This is supported by Madara saying once revived "So it finally happened..."
and Tobi claiming that Nagato's rinne of rebirth used to revive Konoha was "meant for him, not them"
Madara then created Zetsu as a spy to make sure things went according to his plan and told him to get all of Tobi's trust
Zetsu was then assigned to watch over Obito and Shisui, in case they died to get their Sharingan's but shisui managed to give away his sharingan to Itachi while the other Danzo stole
This is partially proven when Tobi is so eager to get Shisui's eye after the Danzo fight
Obito then dying far before this, his eye is taken and implanted into Tobi which explains his similar reality warping abilities to that of Kakashi's
The Theory is way longer but i can't be asked to write the rest xd
