No problem at all!
So sorry to hear that. Candling daily is perfectly safe, as long as you're very careful not to drop them or anything like that, and don't have them out of the incubator too long if you do need to take them out to candle. And try to put them back in the same position so they aren't turned, if you aren't continuing to turn them.
I found it super helpful also, when I hatched my babies! What are you currently feeding Donny? Thats a good place to start, if you need any help there
they will probably be alright, if theres too much of a size differnece, they may have to be separate, but itd be nice if they could see eachother still, through a divide of some sort.
if you havent already, I reccomend giving Donny a little mirror, perhaps a plush toy also, it can help with loneliness with single ducklings, whenever we arent there. Makes them feel like they have another little duck there!
You're welcome! Hope this helps