I am in two minds here.
On the one hand, this particular vegan guest seems pleasant and reasonable, and there's no reason to not bend a little for her. (Though as the OP @GunpowderGelatine has said, they have already sorted it anyway.)
On the other hand, DH and I do know some vegans. (10 in total.. 4 individuals and 3 couples.)
Over the past 3 or 4 years DH and I have been socialising with them, (they have only been vegans since 2015/2016,) we have constantly made an effort to cater to their vegan needs and wants and requests. Often spending extra money - quite a bit - to accommodate them and their dietary requirements. Yet not once have they ever catered to our needs. They never even get a carton of our (cow's) milk in.
They could even buy a microwave 'ready meal,' or a chicken pie or something similar, (that they can just chuck in the oven - or microwave.) But they never do. They always serve us with 'their' food. It never crosses their mind to cater to our food choices, even though we bend over backwards for them.
Whenever I have mentioned it to anyone on message forums before, I get told 'well you can eat what they eat, but they can't eat what you eat,' which is a cop out IMO. Just a carton of cow's milk and an oven ready cheese and pasta bake would do. Or a microwave chicken madras, with some naan bread. Instead, we get their soy milk, and dry nut roast, with tasteless veg, and dairy free dessert. There's more taste in snow than there is in the dairy free dessert they dish up for us.
I know some people will say 'but there's tons of vegan food you can get that is tasty and yummy,' but apart from beans (and a couple of other things,) most vegan food is dire. Just tasteless and bland. A few biscuits and the odd bit of chocolate that's vegan is OK, but the majority of vegan food is yuk IMO.
It's got to the point now where we won't have them around for dinner, because we no longer wish to cater to their vegan needs when they can't even be arsed to buy in a carton of our milk, let alone buy anything in for us that's non-vegan... And we no longer go to theirs. We have been asked a couple of times this past few months but have started to say 'no, we'd rather go out for a meal.'
And a few months ago, me and DH went to this particular person's house, (and she and her DP are both vegan.) We took our own milk for our coffee, and some mcvities chocolate biscuits, as we know they never have anything but soy milk in, and never have any biscuits at all.. Their face(s) dropped to the floor, and she said 'you brought your own milk and biscuits?'' with a kind of
look. We said 'yeah, because this is the milk we prefer and these are our fave biscuits.. You don't mind do you? We brought you some bourbons that are vegan.' 
She just gave me a frosty stare, and the atmosphere was so frosty, that we only stayed half an hour. We always buy soy milk for them, and biscuits that are vegan, and cater to their needs when they come round for a meal. (As we have done with all the vegans we know.) Yet, they don't even get a single biscuit in for us. Then she was arsey with us for bringing our own. 
So anyway, whenever we socialise with the vegans we know now, me and DH say 'we'll go out for a meal' because we are not catering to them any longer when they refuse to cater to us in the name of their 'beliefs.' And as I said, we don't want to go to theirs anyway, as what they dish up is pretty tasteless.
I know this will offend a few people, but I take as I find, and IME, some vegans - not all - are self-centred and entitled, and want things all their own way.