How active is the active area they are in? They may not be used to the commotion yet. Do you plan on having them in this area when they are breeding? If so, leave them be. If you are planning on moving them, I'd put them wherever you will have the nesting location at.
14 hours of daylight is good. Do you have a UV lamp on them or just regular lights? How do you administer the vitamin and mineral suppliment? I highly discourage putting things in the water all the time because you cannot control dosage. My one exception to this is liquid calcium with vitamin D added a few times a week since this is more readily absorbed than a mineral block or cuttlebone.
You can also add hard boiled egg, crushed with the shelll to their diet, this is very good for them! Just not as an every day treat. Egg needs removed after an hour because of bacterial growth.
Something is definitely wrong, because normal healthy lovebirds do not hide in
their nests, and usually the females spend more time in the nests than the males.
Also, examining the pelvic bones of non-breeding birds is highly inaccurate.
Since I do not know anything about the background of the birds, and the conditions
which they were produced, all of my comments are just guesses.
Thanks for posting the pictures.
- You could have 2 females. Obviously, they are not compatible.
- Is the darker bird on the top the agressor ?It could be a 3-way cross: fishers/black-masked/peachface.Occassionally, black-masked/peachfaces are fertile. You will see the black from the black-masked as well as a red-orange band in the front (from the peachface). This might mean that your bird could be 25% peachface. (This has happened in my friend's aviary, when he was given an obvious hybrid.)These birds do not follow the usual nest-building process.
- Getting birds (free ?) from a friend of a friend sometimes means that you inherited someone else's problems.
