How about if you take her out once - try to find a less expensive place, many vegan places offer some raw dishes; I had a raw burger y'day that was delicious and not pricey - and then you could 'cook' once and then make it a personalised salad type thing, ie masses of bowls with different types of food that you mix yourselves. You could offer veggies such as avocadoes (often popular with rawies), celery, nuts and seeds, sprouts, salad leaves, some algae if you like (actually 'sushi' might be something you could make for all of you if you like that, this is a raw recipe not using rice of course:http://www.fromsadtoraw.com/Recipes/RawSushi.htm), parsley, berries, courgettes, herbs, peppers, tomatoes... And then everyone just takes what they want.
I'd worry less about ensuring that she gets protein with every meal. Most westerners eat far too much protein, which is very unhealthy, and most vegetables contain some. She's probably not counting on eating 100% balanced food all the time.
Agree with others that it's fine to ask her for suggestions! Being a vegan myself I'm very used to that and appreciate it. (And unless I know the people I'm seeing I always assume that I won't be able to eat much, so bring something I can eat discreetly if salad leaves are the only thing on offer ;-) )