Wifi - I don't have enough knowledge but glad I've read this thread now as it's put me on guard.
Batteries - I have 2x chargers (4-way AA & 4-way AAA) with both chassis screwed discretely inside a shelving unit. Also supply 8x AA & 8x AAA all rechargeable. Haven't had any go walkies yet but if they do will be covered under security deposit under "other losses."
Have had lots of guests comment on convenience merits of this so I'd highly recommend it.