Another option for main is to go down a pasta route such as lasagne. I've got several really nice vegetables ones and you could really do mini vegetable ones on an individual portion scale for the vegetarians. Just ensure if you do roast veg to use oil not lard.
Also have you confirmed thay both vegetarians are vegetarians and not vegans? There's a considerable difference and in my case I wouldn't actually be able to ready vegetarian even if I was as flexible with my diet as some (for instance my hubby will eat vegetarian if nothing else is available whereas I actually can't dairy to a dairy allergy that causes anaphylactic shock)
Yes they are definitely vegetarians, not vegans A vege lasagne sounds really tasty and could be made quite attractive in individual portions too, I presume also could be prepared ahead?
I did think this morning about pasta options, maybe trying a starter of ravioli, with something other than a cheese based filling, for everyone to make things simpler but then I remembered my fussy mother doesn't enjoy pasta, I think I've got my hands full with this lot lol.