they are not "girls" they are mares, girl is a reference to humans! and in equestria it doesnt matter who you love as long as you love them, we are only raised to think that being lesbian or gay is not normal...its quite sad really...that people even think that way...like you.
I know you said this was mainly due to technical issues (not being able to get it to loop correctly if Pinkie had closed her eyes), but, I actually find it really funny that Pinkie has that "not sure if want" look on her face.
If anything, I'd have expected the facial expressions to be reversed (with Dash looking unsure about the whole thing). Nice subversion!