For myself, I'll address the Facebook thing first. Personally, I'm not into it very much and am very selective about whom I "friend" on there. Generally it is family and career contacts. Most of the time, really, I can't be fucking bothered with it, so if anyone wants to be in touch with me they had better find a better way. Sometimes I'll meet someone who asks me to connect with him or her on FB and I just tell them no. I think it's a pretty weird thing for someone I barely know to do, if you ask me. So, if they want to know why not, I just say, "it's easier to contact me via email or phone. I reserve FB for relatives and colleagues." Even though my situation is different, my point is you don't have to say yes and connect with her there, and you don't owe her an explanation. If she gets bent out of shape over something like that, that's just weird and I really don't know why you had to patch it up after she freaked out. Oy veh.
You could set your privacy settings so that she can't see your posts anymore, so she wouldn't have anything to "Like." I have one uncle who insisted on connecting with me there, and he kept doing the same thing to me, "Liking" everything I wrote. Drove me nuts, so now he can't see any of my wall posts or any of my other Friends.
As for presents, you can tell your husband that she should keep the gift-giving between her and him, and that it's just not the kind of relationship you are comfortable having with her. You appreciate it and thank you very much, but that's just not how you express yourself with acquaintances. Polite and respectful doesn't have to mean chummy and cloying. Oh, and have your hubs tell her that if she is sending something via UPS or whatever, to have them send a notification email to give you both a heads-up, or send it to him at work, so you're not put in an awkward situation trying to explain the delivery again.