well remember rin apparently she fought the hidden mist ninja's and was stabbed by kakashi
and we also know that obito saw rin die so here what could have really happened.
when obito entered the hidden mist he made his own experimental project of reviving rin in his laboratory.
tobi has lots of stuff in his lab so if he really likes rin why not have her body there so here's what tobi did it could be possible that tobi made a hidden mist ninja give up his life to revive rin like what chiyo did to bring back gaara to life and plus tobi made the hidden mist bloody in these days so why not bring back rin.
so by reviving rin he could have rin take another identity and be the next mizukage
all obito would need to do is take off rin marks die her hair and then take swap rin eyes which obito knows how to do and if rin grew up she would look like the mizukage.
also look at chojuro who does he look like
chojuro looks like obito so maybe when obito was mizukage he made a clone of himself called chojuro to protect the mizukage and that's why chojuro has feeling for the mizukage like how obito has with rin and also why the mizukage was trying to let obito believe in himself more like what rin did to obito.(obito and chojuro have the same personality and body structure while rin and the mizukage have the same body stucture and similar personality.)
basically chojuro is just obito clone from the hidden mist to protect rin so in a way obito will always have protected rin and the mizukage is really rin grown up with different hair color and eyes without the marks.
remember where is rin's dead body well it's not in the leaf so maybe she is alive
so do you really think that rin is actually the mizukage and that chojuro is obito's clone
this is a what if scernario