Mites on pet parrots are a rarity and people often cause their birds lung and liver damage by using toxic sprays on them without getting a diagnosis of mites and without seeing any evidence of them. Taking a bird to the vet is the proper thing to do if one suspects mites. I also hope that someday those horrid "mite protector" gadgets that are sold to hang in or on bird cages will be relegated to the past where they belong. The environment of our birds is toxic enough without adding a totally unnecessary source of contamination. Even birds that live outside rarely get mites and indoor birds have almost no chance of getting them. Look to diet and other environmental conditions to determine the cause of of poor feather condition.

They need to get to know each other while in their individual cages first, as you are doing now. You can gradually move the cages closer together as they indicate an interest in each other. I would locate the feeding dishes on the end of each cage that is closest to the other, so that they can "eat together" so to speak.

When they start hanging out on the perches closest to each other, which you can tell by the location of the droppings in the mornings, then you can think of introducing them in "neutral territory". Again, never place them in the other's territory--they instinctively protect their space, even against one of their own kind.

Ideally, you will have an aviary larger than their individual cages for them to breed if that is your intention. They should both be placed in the new aviary at the same time so that neither claims it as their individual territory. Then leave them alone but try to observe from a distance. There may be some harmless "sparring" as they establish their relationship but usually Eclectus do not really fight and cause bodily harm. It may be difficult for you not to intervene in their squabbling (IF they even do it), but it is best to let them work things out without your interference unless you are sure they mean to do each other damage. I know it's a hard call but take heart in the knowledge that vicious attacks between Eclectus pairs are extremely rare. If you can set up a closed circuit TV system, you may be more comfortable with their initial introduction and getting to know each other period. It would be good if you could locate two sets of food and water dishes on opposite ends of the aviary so that neither can dominate all the food. Dominance of food bowls may not be a problem at all, but this is a good precaution to take.

Do not introduce a nestbox until you see definite signs of courtship. Otherwise, the female is likely to disappear into her new "home" and he will not have the opportunity to court her and establish a relationship with her. Then you will get an endless supply of clear eggs, which is a waste of the hen's resources. I would wait until I saw mutual feeding to give them a box. Don't expect to see a lot of mutual preening as you would in cockatoos, although some pairs do preen each other to a degree. When you are sure that they are a bonded pair, hang the nestbox as high in the aviary as possible and where it cannot be wet by rain. Construct a visual barrier of the entrance if you have other pairs in the area. I like the Grandfather style box, 12" X 12" X 24". The boot shape box may be even better in case your pair is prone to diving into the box and thereby damaging eggs. Get them accustomed to a daily inspection of the nestbox but otherwise, give them privacy until they are firmly established as a pair. After that, if they are interested in interaction with you, you can be a third wheel like I am with my pairs. :)

Actually, it is quite easy to potty train an Eclectus.  First, study your bird's body language and you will notice that he has his own unique way of signalling you that he is about to eliminate. Sometimes it is only a matter of the bird getting antsy and shifting from foot to foot. When they are about to eliminate, they usually do a backing up motion, sometimes lifting their tail slightly. These signals are unmistakable. You can time the intervals between poops and learn to anticipate the time that your bird needs to eliminate. If he has eaten very watery foods like fresh fruits and veggies, the timing might become more frequent. Choose a word or phrase to use as your command such as "Go potty" or "Be a good birdie" and either return the bird to his cage or perch, or hold him over a newspaper, potty, or trash can. Once the bird goes on command, use hugs, kisses, expressive language, food treats or whatever your bird likes most and praise him lavishly. Do not punish for mistakes or for not being able to go on command. Use positive reinforcement instead of punishment and you soon will have a potty trained bird who loves and trusts you. There is nothing sadder than a bird that has been "trained" through the fear of punishment. Since it is so easy to potty train birds, it is almost a shame not to make the effort since it makes it so much nicer for you and your friends to enjoy them. Eclectus are such intelligent creatures that sometimes they train themselves after only one incident of their beloved owner showing displeasure at being pooped upon.

Sooner or later you are sure to hear or read the old wives tale or warning about birds holding their poop until they get the command to eliminate. To my knowledge, no one has ever seen an actual case of a bird that refuses to go without the command, so I believe that we can safely file this one with the many other myths that surround parrots.