So, I'd like to give the smart aleck answer first...'other vegans, except they don't eat meat.'
OK, now that that's done with...load up on the fruit. Depending on how long they are staying and how involved you want to get, there's a pretty decent soy sausage casserole recipe that could be made for 2. OTOH, with guests whose needs are so far out of your expertise and offerings, the best bet may be to email them and ask what they usually eat. You may find they don't want much anyway.
If you're wondering how to decide...if it ever had a face, they won't eat it. So you need to stick to the veggie/fruit side of the food pyramid.