Patti, I've been taking in unwanted parrots since 1992 and I can guarantee you that caring for them is ALWAYS a work in progress! It's not only that we still don't know enough about them (and this covers dietary, behavioral AND medical aspects), it's also that there are so many species and they are so different from one another that, in reality, anybody who actually wanted to 'specialize' in their care should concentrate on just a few similar species because nobody can remember the huge amount of knowledge it would take to cover them all. I've always had a mind like a bear trap for facts and a prodigious memory and I struggle every single day (and double and triple check myself) so as not to miss anything (and fail, too!). I can also tell you that, of all the people I know who takes in unwanted parrots, you are the one that has the best set-up, feeds right and provides complete medical care. Rescues don't do as well, Patti, so triple kudos to you!
I would not use any light whatsoever for the night. I did a little research on the specifications for moonlight and, although it's clear it needs to be a blue light because of the wavelength, the wattage would have to be way too low to actually provide a similar light. I used a radius of 5 ft and full moon (just to have an idea, I know you are not going to keep the birds in a round room
) and it gave me a result of less than 1 watt! Where are you going to find a light that low? What I would do is leave the blinds the tiniest bit open so the light from the moon and the stars shines in enough for them not to be in complete-complete darkness.
My house in Pa was smack in the middle of 5 acres covered in old forest (BIG trees) so it was super dark at night but the birds all did great there (not a single tiel had a night fright- not ever!). The other problem I see with having a light reproducing the moon light at night is that the moon goes through phases every 28 days but an artificial light would be 'stuck' in the same one all month long. Do moon phases affect birds endocrine system? I don't know and I couldn't find a single study on it (we don't even have that many on sunlight!) but, as with everything else we don't know about their physiology, I would go with natural, just in case.