Moderator Post (s) for this thread: >Modular renovationbytomh on 07/25/2004
You sound very capable and intelligent so I would suggest you try to sit back and answer questions on a cost and dificulty basis. With the walls open the cost of insualtion is not much and it's staring you in the face - now's the time to do it! So wall insulation is easy - do it now. Dry or whatever black means - rip it out! Floor joist space - yes now it's easy, you get more insulation value and it's not expensive. Vapor barrier - repair it or replace as needed.
Cat odor - I would try spraying the area with a bleach solution or industrial cleaner to break down the urine.