Continuing the discussion from Stories from a beginner:
I think all the features you describe are possible; and most of them are already in one or two (or three?) different variations of Community developed Device Type Handlers for this lock model.
The bit of frustration is first figuring out which one is a good (or the best) baseline and then build upon it.
Each might chime in here and tell you if their variation is the closest fit to your required/desired features. And they might even add the features you request or give you (or anyone else that wants to pitch in), guidance.
The result of this Thread might be some good conclusive reference material to add to the http://ThingsThatAreSmart.wiki