"Honor thy father and mother."
Is that so hard? Apparently, yes it is, for some people.
Facebook is not the issue. Your husband should have simply called each one to say "Mom is hurt, X happened." You can't post on FB and expect everyone to see it and call. Posts get buried. The only way I could keep up with my FB feed is if I check it every 1 hour. Sometimes I avoid FB for hours and a day, because it gets to be too much. So I'm guessing they missed the post.
And, horrors, what if they didn't? What if your husband and you can PROVE they commented on other posts at the same time? Well, that's not productive at all. People have their own, legitimate reasons not to respond to posts. Maybe they were dealing with a million little things. Maybe they would call later.
Then your husband calls them to blame them. Who knows if they even saw it or not.
I agree with Anita B. Someone needs to take the lead and make the phone calls, if it is so hard for them.
My sister (in another state) is a phone person. I am not. I hate talking on the phone. She calls me every day. Or every other day. Or many times a day. I'm busy with 2 kids and a family and sometimes I'm curt on the phone. Sometimes I don't call her back till the next day. Then we are playing phone tag.
She did tell me (years ago) she was hurt I didn't seem to care. She had a point, so I listened and changed my response.
The Marx Bros. were so tight, they called each other every single day, till they died. The conversations went like this, "hey what's new? Nothin'. Me neither. Bye." Sometimes more than once a day.
So for now, let the dust settle. Don't get all passive/aggressive/martyr and wait to see if they acknowledge your birthday. Just do something on your own with your husband for your birthday and Christmas. Don't guilt them. Don't remind them of past hurts.
BSF - Bible Study Fellowship
And I'll share what is helping me, especially with "how do I handle X?" The BIBLE is great. I started taking a BSF (Bible Study Fellowship) class last year and I'm blown away by what I'm learning. Go to their website for more information. I look forward to my weekly class. I learn so much and love it so much. It's not a superficial read of the bible (something I might do by myself) but it's reflective and deeper.
BOUNDARIES
http://www.cloudtownsend.com/articles/scoop-on-boundaries/
Your last statement sounds a lot like me (I have younger children) and this is definitely a problem. I found a book called BOUNDARIES AND KIDS. I have this problem with my own children. I'm taking a church class now on the book. You might want to look at the authors website to read the books they have. It may help you deal with your family.
I would be sad if my mom moved away, but I wouldn't hold on to bitterness about it. (I would put myself in her shoes and see it from her point of view. That is called maturity.) Your daughter seems entitled to have you there for her needs. She has some issues with boundaries, but that might be because you taught her you didn't have any. You were an endless source of giving. People get trained to expect certain things then. And when you say, "sorry, I can't" (when you finally set a boundaries) they go off. That is also a form of manipulation.
Nobody is perfect. Everybody makes mistakes. I don't think you moving away was a mistake. But along the way, they learned certain things and now you are dealing with the after effects. Ugh. I feel for you.
But you can deal with it. Constructively. The books will help.