Your built up floor is not going to stiffen much for having been layered for the same reason that you can bend three 1/4" rips easier than you can one 3/4" board. The layers will move independently esp. with that homosote and mechanical fastening. If you can adhere the homosote both sides with an adhesive it might stiffen but I wouldn't count on it. You could consider going to 1" or even 1 1/4" plywood (makes my back sore to think of it)
As for the wire I have used Simpson framing strap over wires but I don't know that that would be code approved
If there is not much wire you might think about 1/2" ridged conduit.
