If a mongrel mage has selected a bloodline are they considered to have that bloodline for that day? I could see it working for bloodhunting weapon for sure.
I'm specifically wondering if I could play a mongrel mage and pick up the Tiefling's +2 to charisma for sorcerer abilities whenever I pick the infernal or abyssal bloodline
Hopeful bump.
My assumption is it would affect me similar to something like foxes cunning unless I have it for multiple days strait then maybe it would affect my spells per day and such
I'd allow it. It's substantially different from the kind of temporary shenanigans that have been nixed.