Your instinct is right about the rescue. Keep him til he's ready for seed then give him some grains of wheat and milo. If he has no problem pecking them up, you can release him. Still mourning doves are one of the very few birds that do well in captivity as long as there are two. You can keep them in a large (parrot size) cage.

I have been handfeeding two orphaned mourning dove fledglings for almost a week now.

I would love to release the two of them together as they are very attached to one another but one seems to have a slightly injured beak.

He doesn't seem to be in any pain and can eat formula just fine, but his lower beak curves downward ever so slightly, leaving the very tip open MAYBE a millimeter.

If I have to, I can keep the little guy long term, if he heals or forever if he doesn't. However, I cannot continue to handfeed him several times a day long term.

Do injuries like this normally heal? And more importantly, if not, what are the chances that the little guy will be able to eat on his own the way he is?

I have grown quite attached to this little guy and would hate to have to make such a difficult decision regarding his life. I have considered taking him to a wildlife rescue,but this rescue does not usually rehabilitate injured doves and pigeons, and I'd be worried that they won't even give him a chance.