There is a very clear halacha that one is not allowed to invite non-Jews on Yom Tov specifically. See SA OH 514, Yalkut Yosef 512. The only solution presented in the halacha is if they turn up uninvited, one is not obligated to refuse them, although one is still explicitly not allowed to entreat them to eat. One is even discouraged (although bedi'eved permitted, see YY 512:3) from making them coffee, and one is not allowed to add food to the pot once they turn up uninvited (see Rama 512, MB 512:11, although compare to Chazon Ovadya footnote on p.41 which permits it, yet contrast with what he wrote in Halichot Olam Vol II p.18 forbidding it).
So, except in the rare case they show up uninvited and barge their way in, in which case one might not even be able to feed them if one hasn't prepared enough, for all practical purposes it's almost impossible to host a non-Jew for Yom Tov.
For clarity, this is not to do with any form of discrimination, it doesn't even have to do with old paganism and idol worship. It's purely based on a hard reading of a verse in the Torah (Shemot 12:16 and the word "לכם") that implies that, in the special provision to cook on Yom Tov (as opposed to Shabbat), one is only allowed to do so for a fellow Jew. Therefore, it becomes almost impossible to invite and host a non-Jew within halacha, and this is the reason, not discrimination. Inviting a non-Jew for Shabbat is not ruled out because of this, and Shabbat is a holier day than a Yom Tov, and one is not required or even encouraged (as far as I can tell) to actively refuse hospitality to a non-Jew even on Yom Tov.
Does anyone have any solution on how to deal with this on a practical level? How are converting families supposed to learn and integrate on Yom Tov? What about if one has non-Jewish relatives, or non Jews in one's household?
How does it all work?
Surely there are some kinds of solutions but I couldn't find any in the halacha.