But that doesn't look like rinnengan all the rinnengan we have seen look the same but you don't answer my question why fought hashirama for his cell if you don't need it?
Part of madara's plan has to do with the ten tails... Uchihas can't host bijuus because they don't possess the sage BODY... So madara needed the sage body (senju cells) to host the ten tails.
The whole point of the manga has to do with the sage's EYES vs the sage's BODY.
Uchiha = eyes powers
senju/uzumaki = body power
the sage powers were split in two among his sons...
The senju ancestor inherited the sage body so they can host the 9 tails and perhaps the ten tails
The uchiha ancestor inherited the sage eyes so they can awaken the ms and rinnegan.
Gaining cells will only improve your BODY power not your EYE POWER.
If your theory is right then danzo would awaken the rinnegan, since he possess both powers.