Is there a possessive form for each gender? I've seen endings with -a, -i, -e, -yz, -ys, and -or so far.
Yes, of course. This might be a bit much information for the moment, but you can find the forms here: https://wiki.dothraki.org/High_Valyrian_Noun_Declensions
What's the difference between ñuhor/ñuha/ñuhyz-ñuhys: Like... They're used in different chapters? So you would use ñuhor only with the words in this chapter? Related to the sea or something? I feel pretty daft for asking but I need to know