I've only gotten tenpenny and Jericho from lunch boxes so it makes me think that's how you get them all.
How exactly does the radio calling work? I've seen it in countdown multiple times, but I've only gotten one outsider respond. I have two CHA-optimized characters in there (bolstered by Nightwear), and I've upgraded it once. Should I maybe make it a 2x room and have more people working it?
It seems like the counter indicates when the next signal will transmit. Your chance of that signal being heard increases with room upgrades and charisma rating of those in the room.
The only way to improve the chance of attracting a dweller is to upgrade the radio room.
I read somewhere that luck affects caps. If a worker has high luck, you may also get caps when collecting their resource.
I think Luck is also a factor on the success chance of a rush job in a production room.
With Colonel Autumn manning the radio station, he managed to bring me a dweller with 8 strength, 7 luck and 3-5 in every other stat, although it was just a randomly generated character rather than a legendary survivor. Still very good though!
I have noticed same for me: firstly i though i got it from cards, but it's not listed in Dwellers list.
David Payne: have a look at link, i don't have any ability room: http://s24.postimg.org/rszx81ysl/IMG_2307.png
i will write later his stats, cause he is backing from wasteland and i can't look.