Sutekh wanted The Doctor away from the TARDIS when he manifested himself. He's obviously been parasitising it or piggybacking on it. Hence the planted image of somebody who The Doctor might think is his granddaughter. Throw in the anagrams to make UNIT think the same and you have the trap.

I would imagine Sutekh doesn't want to confront The Doctor directly until he's up to full emergence.

Who said Susan was human?

I am also glad that it wasn't the Daleks/Cybermen/Sontarans again! The Masters' arc was definitively over in The Doctor Falls and the 'incarnation' that caused trouble for Thirteen was another both unnecessary and unforgiveable thing that Chibnall did to Jodie Whittaker. If RTD brings him back he' ll need a Hell of a good reason!

We'll probably eventually find it was Mrs Flood who dropped Ruby off at the church. The why we won't know for another season- or maybe around Xmas - because I suspect the solution of that mystery will tie in with Millie Gibsons' departure from the show.

Mrs Flood breaks the fourth wall because she's probably Deadpools' Mum!