"... I found a hose that came apart - it goes from the intake manifold into a little metal cylinder near the fuel injectors (?) at the front/top of the engine..."

That little cylinder is the fuel pressure regulator. The hose is a vacuum hose that has an effect on fuel pressure when the the engine is under load, but its absence won't keep the engine from starting. It's good that you repaired it though.

It's possible that when your wife ran it low on gas that it ruined the in-tank pump. Open the trunk and listen carefully back near the back seat bulkhead. Have someone turn on the ignition. You should hear the pump run for a couple of seconds. The same thing should happen at the main pump which is located under the car like under the driver's seat. The car "might" run with a bad tank pump if you have enough gas in the tank, but it's not good for the main pump to do that.

Also, check the fuses. If they are the knife blade type, that's not too bad, but if they're the little barrel shaped ones with pointy contacts on each end, take them out one at a time and clean the tips and the holder tabs.