Try to locate where the faucet is leaking.You should be able to unscrew the top of the faucet and remove the stem.the stem has a washer on it that may need replacing.If that doesn't do it replace the faucet Good luck.

Pavers are a good idea, old rail road ties work good flat stones or slate could also work.

You may get by with removing the lower one to two feet of dry wall to clean out any old debris.Be sure to check for dry rot while wall is exposed,always wear an appropriate mask. Next prime all the walls, ceilings, and if necessary the exposed wood with a sealer that will seal up odors. It is called Zinsser's "B-I-N Primer", which is a white-pigmented shellac. You can clean up with regular household ammonia just be careful of the fumes.

As for the electrical I would try to expose the panel area, mark or number the wires replace the panel and reconnect wire.Make sure main power source is off or disconnected.If your not comfortable with this call an certified electrician.