I've only read the first post so far and wanted to say that I totally understand the anxiety to begin with, I've been anxious for months about this as I'm on a very limited diet while I wait to find out what I reacted to
There is no excuse for the lack of thought or care from your family!
My parents have made a safe shelf for me, and the smallest drawer in the freezer is a safe drawer for me. They have a bowl of safe snacks on the table for me so that I feel included with the other snacks being on the table (mine are in a different type of bowl and all sealed so no risk).
When cooking they are triple checking everything they use with me first, doing things like washing hands and using clean silver foil on trays without me asking, have a dedicated chopping board for me
I'm an adult, I'm sure if it was a child that they would probably have just gone without any allergens themselves for the whole time just in case, and I'd do the same, because you don't know what a child is going to put in their mouth
So no, under no circumstances are you being unreasonable, but they definitely are! They don't even seem to be making a token gesture of trying!
I am sorry that you are in this situation, if family members didn't care enough to make it safe for me or my DC then I wouldn't be spending time there in future