Soaknup what you can, use white vinegar for the smell..then steam cleaner (that thing about it smelling whenever it gets steamy, etc..well steam it now and get it all evaporated out... You could try ironing for the same result)
Little gets! Boys you say. Is there something in that, especially marking a bed/sofa. Entire?
The brown one seems to be owning the other, looking the dominant one. Try a felliway, dog version, can't think of the name, he will pee to mark dominance if feeling anxious about that?
You had them long? Trouble is dogs who mark pee, always have some ready for the job, and no amount of letting them out will resolve it.
Restrict their area to downstairs, say, and not allow any unsupervised access. I doubt they would do it in front of you so its gonna have to be about breaking the habit through lack of opportunity.
Do they vie for your attention or get into scraps with each other over you? Like when you first walk in a room?
I am doing some tt just now, but of the particularly smelly, and persistently so, cat piss! We have one doing training to use our loo. Have every sympathy for the lividness of the situation!