One thing for sure Karen, they will never be consistent with behavior and will go through changes daily, weekly or monthly. They may be even keeled in temperament for a year and more and then have some changes in behavior. I think that can hold true for many species of birds. I certainly never thought I'd ever be able to touch Henry again after he matured and became so aggressive towards me. That lasted for five years from the most extreme aggression to flying at me in full on attacks to being very indifferent towards me and still yet threats. He's been in a different "zone" for almost two years now. He nicely takes his wood blocks and wood chews from me, doesn't mind my business around his cage as I wipe his top pan and takes direction from me to move from one outside perch on his door to the perch over his door so I can place his evening meal. He's only inches from me ... it could go horribly wrong as you well know. His food is everything but his manners suggest patience so I am ever watchful. What I can't get used to is when he drops that wood and wants me to scratch his head every evening before I'm done with his cage and before he gets that food. I can't STAND having him sit over me supervising my every move while he waits for me to scratch his head. If I could redirect his attention to go back to chewing his wood I'd be happy knowing he's busy but at the moment he's pretty insistent on getting his itchy head scratched which I always oblige to maintain a relationship with him... as long as he's making happy grumbles and his eyes are closed. If he opens his eyes and watches me while my hand is on his head I quit and call it a day.
My point in sharing about the changes in Henry is that they do go through changes from good to bad back to good and so on. I see your confusion about what to do because the opportunity for injury to Luv Bug is at risk, even with diligence things happen quickly. Puffin may be more dominant than Luv Bug and is establishing her territory. I see it with my two female crimson bellies and they've known each other their whole nine years of life here. Ruby is dominant... always has been. Scarlette knows to back off and move far away from Ruby and this whole interaction is the number one reason Scarlette is a timid girl. This is never going to change for these two and may never change for your two Too's. If you are comfortable giving it some time and testing the waters with taking turns and seeing that Puffin can be made content locked in while Luv Bug is out. I'd reserve some special toys or food for that time for Puffin so that she's occupied and doesn't care if she's locked up during that time. You know what is best for them both and we all support you no matter what decision you make. Big hugs for all of you!