I need some advice relate to how much I should deviate from canon when it comes to characters from the books when it comes to unmarried characters and giving them spouses, specifically the Ryswells and Jonelle Cerwyn.

I feel like there is a lack of fanfics that focus on more minor houses in the contexts of the books and the shows and I wish that was a bit different since I personally am a bit burned out of fics that focus on the major houses. And I thought to personally change that. Over a year ago I posted something on The Citadel about a rewrite of the Telltale Game of Thrones game and since than I haven't done anything since I got trapped into the trap that is trying to merge the information from the game, from the fanmade season 2 fanfic and the CK3 AGOT mod. I think it would be interesting to show how the minor houses of the North deal with the aftermath of the Red Wedding and the Ironborn invasion. There will be a lot of changes, but I will not talk in details about them because it might take to much: Mira is in Barrowton with Barbarey, the main antagonists are still the Whitehills (but they are less 100% willing and more it is you or me, they are Glover vassals and also the role of the Boltons in the Ironrath storyline will be taken by the Ironborn).

My actual question is more about if I should include some OCs that are married into canon houses. I am vexed by how none of lord Ryswell's sons are married (Roose makes sense since he is the youngest, but for Roger and Rickard is harder), Jonelle Cerwyn to a lesser extent to. Aside from spouse I will probably need to also add some children born of the union. I am looking for ideas related to that, I would like some suggestions for possible spouses for Roger and Rickard Ryswell as well as Jonelle Cerwyn that can somewhat fit with the canon. This is a bit where I draw the blanks.

Sorry if this is too long and also for it being more on the me just talking about the ideas and the help being for a very minor part for some people, but I like genealogy and it's important for me. If I said something dumb, please also correct me, I am not above making mistakes. I wouldn't mind to hear if anybody has any suggestions relate to what I said about the rewritten storylines, but that isn't my main point.