I hear you abut the whole hanging thing. I paid for Rboy’s driver for the keypad but found I much preferred the community driver from @hmorsti so I went back to that.
I would think the sleeping until the motion sensor activates wouldn’t pose much of an issue as long as you keep that fact in mind when considering placement. Unless you have a bunch of doors your family members frequently exit from that would make checking the keypad inconvenient – and since you’re using the nightlight I assume you’ve already figured that bit out – then you can mount the keypad wherever makes the most sense for your family’s movements. We have 3 exit doors in my house, but really only use one so I have the keypad mounted so we have to pass it on the way out. If we still had housemates, we’d use the second rear door more often and I’d just mount a keypad near it.