Welcome back crazylady12.
First, may I ask a favor? It is difficult to read posts that are huge blocks of texts. I'd appreciate it if you'd put your post in paragraphs. I think more people would read and respond if you do.
I'm afraid the only "help" I can offer is to suggest you just let the family relationships develop as they are rather than how you want them to be. It seems your husband and your 1st BIL's wife don't want them included on the vacation. I think you need to respect that.
With that many people in a family, there are certainly bound to be issues. I'm not sure how you can help that.