I'd certainly think that if it was your coffee, giving it up for a few days would have demonstrated it, so I doubt it's that.
How much can you leave her alone (in a safe space!) before she becomes distressed? At all? Might be worth practising that (leave her alone but just not long enough for her to get upset about it) and gradually extending it, in the hope that she might sometimes just put herself to sleep if she's on her own and tired. I know, but stranger things have happened, and being able to play on one's own is a valuable skill to have anyway ;-)
Personally I'm not against some screen time; I think you've said that you feel differently, but it might be worth thinking how strongly you feel that and why, and whether there is something you would be happy with. At this age DS used to love the Baby Einstein DVDs, of which I like just about everything except the name! Visually interesting with interesting music, no worrying content, to my mind, and he used to enjoy knowing what was going to come next.
I think in your place, though, I'd be doing everything I could think of to get DD to sleep before 1am. You mentioned that there's a lot of noise and disturbance when DH comes home - I wonder whether you could change anything so as to minimise that? Reading NCSS for the sleep cycle info and seeing whether you can adapt it to fit your DD might be helpful, as you'll probably find there are stages in her sleep cycle when she'll wake at the slightest noise and other times when she'll sleep through much more. Maybe if you experiment with when you start trying to get her to sleep, you can arrange that she's in deep sleep when there's noise, and she'll stay asleep?
