Floor insullation.

I purchased a 1978 DBL Wide and need to replace the sub-floors in the kitchen and dining room. When I pulled up the sub-floor I found the - I think its called a Belly Pan, not sure though - insullation is located under the joists, 2x8, leaving a cavity between the insullation and the sub-floor. Should I lay in new insullation, there by filling the void, and should the kraft paper backing go towards the floor or the other insulation, and should I then put a vapor barrier across the joists. We have a critter problem here (Feral Cats!! Trapping and taking to a non-eutha****a (sp?) habitat) and the underside smells horrible so the more I can close that area off the better until I stop the critters and can finally air it out. Thanks for any help, I know its a lot of questions.