Hi there, and welcome! 
What do you mean by a "mutt" Miqo'te? Do you mean half Sun Seeker and half Moon Keeper? Because yes, that is totally possible. Other combinations, such as Miqo'te/Hyur, also seem to be possible. There is an Elezen/Hyur biracial NPC, for instance. One thing to keep in mind if you want to play a character of mixed race (or even, in some cases, mixed clan) is that they are likely to face discrimination. But they do exist in the lore.
Edit: I had forgotten that there is a Hyur/Miqo'te NPC too. So that's definitely a thing, even though it's rare. Not that that was your question...
What do you mean by a "mutt" Miqo'te? Do you mean half Sun Seeker and half Moon Keeper? Because yes, that is totally possible. Other combinations, such as Miqo'te/Hyur, also seem to be possible. There is an Elezen/Hyur biracial NPC, for instance. One thing to keep in mind if you want to play a character of mixed race (or even, in some cases, mixed clan) is that they are likely to face discrimination. But they do exist in the lore.
Edit: I had forgotten that there is a Hyur/Miqo'te NPC too. So that's definitely a thing, even though it's rare. Not that that was your question...
Michaux Vidal - Oyuna Qestir - Tatsu Kaisuri
Arnvi Sunblade - Noriyasu Kuroda - Lucien Lemaire - Bren'li Arhys
(See Tumblr for Character Profiles)
