Blocked at work, but if it's the Cersei theory then I've seen it before.
A bit far-fetched, but even if true, there's no way Cersei is giving up her crown to anyone now. Child or not...
The writers are closing out so many characters now that anything is possible which is the only reason that I’m alluding to this.
It would be in a bad taste to see the Golden Company turn on the Lannister’s. Yes, the Lannister's have debt, but no one else are in the position to settle that debt. As it stands, the Golden Company have no reason whatsoever to break contract unless Qyburn have discussed terms unbeknown to the audience. The undead is now irrelevant, the Night King is dead and the Long Night is no more, this isn't clause anymore to break contract.
What we do have is the Ironborn in war with another, but is by large sided with Cersei thanks to Euron. There is no more Dothraki, a diminished Unsullied and the Northerners and their allies are pretty much worn and tired. They have two dragons, and Arya.
The Golden Company on the other hand is the praetorians (without elephants, which doesn’t matter in any case), the unrivalled elite. Though the Golden Company is payswords, their contract is their oath unless an better opportunity may arise, which there isn't, and even they will make the Unsullied's balls shake. They are the best soldiers and the best strategists.
More to the Lannister's... they have a zombie, giant zombie that is, who may be more undead than the undead. Qyburn also seems to be the better hand than Tyrion and they also have a Pirate, with a nation, who have zero Fcuks to give unless it is Cersei. Not only are the Golden Company premium soldiers, but Euron have experienced many things unbeknown to Westeros sailing and battling on the seas, and raiding where possible, with the Ironborn. Cersei is now strong.
Yara, what is she going to do, call up a mate or two at a bar?
When it comes to a battle, the Lannister side is pretty much now dominant. The question is what can be done to unravel this advantage? Blood...
Bron is still to make up his mind. Companionship or an castle, whichever, but I doubt he will shoot his buds.
What I do believe is that The Mountian is going to tick his kill list... then Cleganebowl.