Fallout – Living quarters limit in Fallout Shelter

Just got a loading screen tip in the game (the wording may not be exactly the same, but the general meaning should):

Dwellers run on food and water. Rooms run on Power.

This is certainly an official source, although not a very in-depth explanation. From this, one could draw the conclusion that rooms consume power regardless of occupancy, and only dwellers use water, even if this isn't explicitly stated.

To further investigate the details (unless some other source is available), I suppose someone will have to do some science.

Edit: It appears the good folks over at /r/foshelter/ have done quite a bit of science.

Some key points relating to the resource consumption (not absolute facts, but probably close to the truth):

• Food/Water consumption is 21/hour per dweller in the vault (so explorers don't count). This means a L3 full-size Nuka-Cola plant can supply 100 people with food and water.
• Power consumption is a bit more complex, and isn't fully explored yet, but it seems to change with the level of rooms. Still unclear if elevators and other things consume power. For now though, don't build more/larger rooms than you need if power is an issue.

There are a lot of other interesting points made in the thread linked above, so I really recommend checking it out. More detailed information is available here. If they keep the work up, this may be the go-to resource for data on the game.

Dwellers dance when they are about to make a baby.

Given that pregnant dwellers can not get pregnant, no. Pregnant dwellers will not dance.

I have confirmed this with a GameFAQs forum post, where a user advises on how to complete this objective quickly, and without the issue of having to worry about overpopulation.

TL, DR: As soon as the dwellers start dancing, it counts as them having danced. Immediately move one of the dwellers to a different room, then immediately move them back. The "baby making process" will reset, and you will have made them dance, without getting one of them pregnant.