Temeraire doesn't know what Valentine's day is but he'll like it for sure because omg a present. Envy knows what Valentine's day is but has managed not to encounter the Japanese version of things yet! So he's going to be very confused to get a present from her haha.

And I can definitely throw them at Mayu and see how that turns out! Envy for sure, since you're right he does have a bit of CR with Mio.