Toilets, Sinks, Showers, Tubs and Disposals - Tub - Two problems, not sure if related or not

I have a two year old double handle single spout faucet set with a pull up spout diverter. Unsure of brand. Lately, have noticed that the spout is leaking fairly heavily from the cut out underneath where it is attached to the pipe. This happens both when the tub is being used, and when the shower is being used. The water runs down the tiles, over the grout and then over the tub overflow. There is no leaking whatsoever when the taps are turned off. Any ideas as to what may be causing this? Problem number two. I have noticed water coming through my basement ceiling. I initially thought I had a drain problem, but then I noticed the leak, and I'm wondering if the two are related. I don't have easy access to the drain pipes, as I'd either have to cut into a lath and plaster wall, or (from below) a stucco ceiling in which I know there is some old knob and tube wiring lurking. I'm hoping there may be something I can do from inside the tub?? The problem bathroom is a fairly recent reno, the tub is steel, and surround is ceramic tile over concrete wall board. Any help gratefully appreciated.