Greetings...
I'm a rookie at this, so...
I agree that horizontal firring strips would be a bad approach for the reason you stated.
I don't think house wrap is the right approach. It is intened to reduce air infiltration into the building. It would not make a very good drain plane.
I would not attach the vertical siding directly to the plywood/sips. Instead, I would use commercially available "drain plane" between the siding and the plywood/sips. This material will hold the siding slightly away from the plywood/sips for drainage.
Considering the sising is far from water tight, I'd be tempted to consider treated plywood or treated plywood on the exterior of the sips.
Hope this helps.
Joel
