Aww, that is exceptionally cute and I don't envy the situation, I have experience with ear plugs/alarms/cats/kids waking up at night, so I can appreciate the fun and games here, although only in an isolated manner rather than the composite problem you are presenting.
I think ultimately I'm in the the "doesn't daughter just walk through to Mum if she needs something?" club, and agreed unless there's some additional reason she needs tending to then one probably wants to snuff out the source of requirement (however admittedly adorable) rather than treat the symptom/add a devices layer to such treatment.
Mine did the walking through needing a cuddle/water/whatever from 2-5 and we had good success through incentive. Might not work for yours or if there's additional reasons why she needs to be tended to but with ours a star chart attached to her door right in front of her face as she's opening it, with stars received for each night and rewards given at certain milestones - was just the ticket. If she really needed attention she'd still come out of course but generally this worked a treat in the space of a handful of weeks and went from every night multiple times to zero and a happier camper overall. Then again, every child is different and so is every parent, so feel free to tell me to STFU