Cracking theory works well and gives a proper reason for the creation of the Vale yard by the time Lords as they see the doctors actions as a act of betrayal. hell have no fury like rassilon scorned

The TARDIS didn't choose to look like Suranne Jones, the TARDIS was downloaded into the character Suranne was playing at the beginning of the episode, so that House could eat the TARDIS without it causing mass destruction.

I personally don't buy the 'Missy is the TARDIS' theory, but I can see some compelling points - and more importantly: I don't have any alternative theories of my own yet.

The Tardis as a "living woman" was fine for a one-off - to do it again would suck all of the wonder and romance out of the concept and they may as well rename the show as Doctor Herewegoagain.

We saw the Dr "time scoop" (if that's the correct terminology??) Journey Blue just before her death into his Tardis. Mssy appears to be doing exactly the same thing. My guess is that the garden is her Tardis and Missy is The Rani.

I'm guessing that all these characters who died are being harvested to be converted into Cybermen?

When we see them In Missy's garden it's possibly something going in in their minds while under cyber-conversion. A bit like being in a coma perhaps?

Rani...

I get the feeling from the episode trailer for tonight's episode that it's going to be somebody significant like that. Simply because The Doctor asked "Who are you?" which felt like a set up for a big reveal.
If she's revealed to be an unknown of before character then the answer to that question would provoke a shrug of the shoulders from the viewers.

I'm hooked on the bracelets so it's got to be Rani. I will happily admit I'm wrong and my obsession with her bracelets has been a red herring..