in your opinion, do you think yoga may actually help? we have been considering that option as well.
Yes it will help if you don't over do it.
Do not lift weights! Weight lifting might make you look good but it's not functional strengh. Weight lifting is the best way to destroy your shoulders and back.
I have done Yoga but I prefere Matt furey excersises. Less time, in the privacy of your home.
The books Combat Abs or Combat Conditioning would be great. Start with the Magnificient 7 and then do the wrestlers Bridge for example.