That's an interesting point you bring up about the views of the wizarding world differing to the Muggles. Now I think about it, wizards marrying their first cousins seems to be fairly commonplace, at least among pureblood families. Sirius's mother didn't even have to change her surname when she married, as her first cousin was also a Black! I'm not sure Harry and Hermione would see it the same way, though, especially as I imagine them all bringing up their children very much together. I think they would see Hugo and Lily more as brother and sister in all but blood.

I will definitely write more Hugo, but I'm not sure when/with whom yet :P Thanks for commenting, glad you enjoyed it!