Lots of people like black pudding, which is blood pudding, which I would probably eat and enjoy if someone served it up disguised so I couldn't see what it was, cow heel was a delicacy in my part of Yorkshire, as was elder [udder] which is ok, and tripe which urgh, my grandmother loved it, trotters too. The Chinese and others eat chicken feet and given a choice I'd go for a trotter or cow heel at least there is meat on them, chicken feet are probably like crackling.
Roadkill you have to make sure you skin and cook swiftly so not stuff that's been on the side of the road for days, maybe go for something that wasn't there the previous evening, round our way it tends to be pheasant or deer, maybe it's still warm, don't hang it. Never had jugged hare, I'd not want to kill a hare just to eat, but have been given rabbits shot because there were so many of them and if you didn't cull them the foxes would
Yes grapefruit no good for those on various medications, green leafy veg you have to be a bit careful of if you are on blood thinners, it is good if the hostess asks beforehand if there is anything you can't eat for medical, ethical, religious or just can't stand it reasons, and if she doesn't you tell her, and it would be good if she gave you an idea in good time what she was planning just in case there was something surprising that you couldn't have. If she doesn't then for heaven's sake let her know of any restrictions so she can plan accordingly
Really a hostess ought not to serve something she is cooking for the first time at such an occasion, and if it is something unusual ought to mention it before she gets the ingredients.