Rosby to go to Roslin and Edmure?

[dragonstone]

Only a theory but I think it could work its way into the plot quite smoothly.
I say this because:
1) Recently deceased Lord Gyles left no heirs
2) Roslin's mother was a Rosby (maybe sister or 1st cousin to Gyles - relationship is never mentioned however I can see that being a fairly even match to powerful(ish) Lord Walder Frey, but a distant Rosby cousin not so much), probably making her claim a superior one to that of the Stokeworths (something about being 3rd cousins or something like that - according to Falyse before Qyburn phucks her up).
3) Cersei or whoever controls the iron throne may see that this would be a dignified outcome for a high lord like Edmure Tully, would be close enough to KL to allow for an eye to be kept on him and given that it appears to be rural, Rosby is most likely not densely populated and would therefore be harder for Edmure to raise an army of any notable size on his own.

Now, I say this because i think it may be of greater significance that Gyles left no blood heirs and it seems like no accident that Edmure's pregnant wife is half Rosby. To be honest, I don't think either detail was plopped in to fill pages (because god knows there are enough pages as it is!)

If this were to happen, and I stress IF, and IF one of the remaining Starks or unCat or the Blackfish were to end up with Dany, then were she to launch an invasion Rosby under Edmure could be convinced to back her. Now of the remaining regions that I can think of in the crownlands: Duskendale is controlled by House Rykker - Targ loyalists in Robert's rebellion; Stokeworth is run by Bronn, so assuming Tyrion does end up with Dany, it should be fairly easy to bring him around (also think the fact that Stokeworth ended up with Bronn is no page-filler); Crackclaw point is mentioned by Dick Crab to be loyal to the targaryens; Dragonstone, should be easy for Dany to take with dragons.

So, all that considered, if and again I stress IF all or most of what I've mentioned falls into place, that would effectively put the entire crownlands against the Lannisters, effectively putting them under siege in King's Landing. With hostile Dorne to the South, divided, semi-hostile Riverlands to the East and potentially hostile Vale to the North, King's Landing is not looking all that secure...

 

[Boaz]

Unless some form of Stark, Tully, or Arryn king or coalition rules from KL, Edmure will never have a castle to call his own. The Tullys have run afoul of the Lannisters, the Baratheons, and the Freys by their association with the Young Wolf. The Tullys also burnt their bridge with the Targaryens.

As Jaime noted in AFFC, any son born to Roslin means Edmure is expendable. His son will have the Tully name, but he'll also have Frey blood... and can be brought up as a Frey, a fast friend to the Lannisters.

Roslin is another matter. As a grand daughter, neice, or whatever to Lord Gyles, she could be married (once Ed is dead) to any lord the Iron Throne wishes to reward. As half-Rosby she'd tie into the Rosby bloodlines and help insure the loyalty of the Rosby bannermen and smallfolk.

But then again, the same could be said for Roslin's older brothers. Perwyn, Benfrey, Willamen, and Olyvar are far down the list to inherit The Twins... so Rosby would probably be a coup for any of them.