Yeah I'd rather not pay YQ or just pay for Y. Ideally I'd be fine flying Y on such a short trip if the taxes are low enough. 2-3 hour train ride sounds like t would kill PHZ. I'll check Sheraton in Davos.
I'm fine either seeing or doing. Seeing is easier as were plus 2 toddlers, but doing isn't out of the question...
BUD sounds perfect for you.
Short flight, one of the cheapest places to fly to, luxury hotels are not expensive (check out the boscolo there), from the cheapest destinations in europe, beautiful city, enough but not too much to see in 1-3 days, kosher food...