I would say the Usos are heels that have mutual respect with the New Day after their feud. They will still be ruthless, but when it comes to New Day, they will have some fun.
Talking Smack is just them being themselves though. It also just shows that not every heel needs to have a grudge and hate every babyface, as evidenced by their interactions with DB.I don't think it's that thought out. The Usos have always been doing backstage segments as faces and Talking Smack too when that was a thing. Only time they do anything heelish is for promos in the ring and when they try to look tough when walking out.
So Mojo is a heel? Oh well