Kirsten I'm glad the peace has started and I'm especially glad that they initiated it. They knew they were in the wrong or they never would have made the first move.
I think you may have really gotten point across this time. At least I hope so!
It is wonderful of you to understand the reasons behind Reinhold's behavior. It doesn't make it right but understanding why makes you a better person.
I agree with you that if it's possible you should try to resume relations with them. She is your mother and you are so right when you say the day will come when she will no longer be here. I would hate to think that later you would have regrets if you didn't attempt to mend fences.
They still MUST abide by your rules in your home. That is simple respect and everyone deserves that. Even though you are a grown woman they still see you as a "child" and are not regarding your feelings. That is wrong on their part and that needs to change.

You are a wonderful person, a wonderful kitty meowmie, and I'm sure a wonderful daughter. Don't ever forget that Kirsten. Every person deserves to have their wishes respected and absolutely in their own home. Stay firm in your beliefs but keep peace whenever you can. You are the bigger and better person for it.
{{{HUGS}}}