Erin, wow. That is alot to come at you at once.
Don't freak about the flowers just yet, wait until Monday and I am sure they will have fixed whatever screwups they did.
Your dress will be fine. It fits, it's just tight. Just remember that it zipped up and that is all that matters. You will be a gorgeous and beaming bride on your wedding day!
Re: your ex. I would def call the family. There aren't many people in our lives that effect us they way that first real boyfriend did. I am a huge beleiver in, everything that has happened makes you what you are today. And those were very formative years you spent with him. I have an ex that is just like that. There is still some connection there and probably always will be, but we both moved on a long time ago. So I feel our pain. I would be devestated if something happened to him. BUt I wouldn't hesitate to reach out to the family.
I send you good thoughts, big hugs, and the courage that you might need to reach out.
(Also keep in mind that if you don't want to get into painfull stuff with your exes family, that can wait, you wedding won't.)