Okay. How much leeway am I permitted for developing advance information? Very very little in DW (which is the specific PbtA game I'll be building this from, since it's the one I've run for several years and know best) ever occurs without preceding context. The only thing that doesn't occur with (as much) starting context is whatever things begin at the very very start with, since (naturally) there hasn't been between 1 and umpteen prior sessions to establish that context.
I assume you will want examples of lock-picking that occurs in the two scenarios you laid out--a house which is known to have fallen on hard times and thus have no servants present (bit unrealistic, since a large house with no servants would likely just be shuttered rather than lived-in, and thus the whole scenario has completely changed, but I digress), and a building of some kind (unlikely to be a country estate) which was once a large residence but is now an abandoned building taken over by (semi-)organized ne'er-do-wells? Are there any other scenarios you would like me to explore?
I'll warn you, even by my usual standards this reply will almost certainly be very long, because I'm going to be examining at least two very different scenarios and exploring a variety of possible pathways GMs could take things. The actual number is "nigh infinite", but I know you want specific, concrete possibilities, so that would be my focus.