Looks like one of yours is a yellow faced blue? The other a cinnamon wing maybe? Definitely lighter in the wing markings.
I don't usually see mating. It's usually quick. I see lots of feeding and sweet talking. If you are interested in breeding generally you need to give them a nestbox after bringing them into breeding condition. I used to sprout seeds for mine. I also think time of year is important too. Mine are currently molting.
Yes! One of my blues is Yellowface. I didn’t realize that was a mutation until I started reading that site.

Now I’ve been reading for hours, and watching videos. I think I have a Yellowface cobalt, a greywing sky, and a grey green Opaline. (Saw cinnamon, but don’t think any of mine are, but I’ll re-check that)
Still not positive on everything, but I’m learning! Lol
Beauties! I see pied and clearwing? More of the mutations I was just reading. So much to take in! The combinations are nearly endless. I’m fascinated.