Why the hell would you take newish bikes with 11 speed and convert them to 12? What advantage do you see? That is a lot of money to change two perfectly good bikes either of which I would love to have. Don't do it. And ask yourself too if they want it, or are they happy with what they have. "Honey, I'm putting 12 speed on your bike", "Why dear? It is perfectly fine the way it is". So, who is actually using the trainer? Are you all using it are is it just you?
My wife wanted to use my trainer and did it 2 or 3 times on my bike. When she realized how hard it is in ERG mode to go above the FTP I set at 140 she gave up. 140 is pretty low and she didn't want to take the FTP test so I had nothing else to go on.