Having three budgies is always going to complicate things. As in your case, two bond and the other becomes a 'third wheel'.
Firstly, as your greens came home the same day, I assume they might be from the same breeder or pet shop so be wary that they may be siblings. If they are living together, that's fine but bare this in mind if you ever want to breed or an egg is ever laid.
The sleeping tent needs to come out of the cage. Budgies toenails can get caught in it. Budgies also don't need to sleep in a tent. They perch on branches in the wild, so putting tents in there is not needed. Budgies can also digest the fibres on the tent.
You can get the budgies a nice swing.
My budgies love this swing as they can go on the top as well as the actual swing platform.
The best idea is to remove your yellow lutino back into the other cage. If it's not the recommended size, you'll want to look at getting a new cage.
You should give her a chance to settle into the cage alone. Just because she doesn't get on with the others, you don't have to give her up.
Has she been violent with the others?
Has she drawn blood from the other budgies?
If she has, she needs to stay in her own cage. She can't be housed with another budgie at all.