Attic Insulation Method -Climate Zone 4A

Hi, I want to re-insulate my attic in the southeast. Most contractors are pretty firm on either spray foaming the roof decking, or blowing in insulation on top of the insulation and plywood that is already there. Part of the problem is there’s so many palmetto bug roaches, previous rodent activity, etc and I want to make sure everything is cleaned, and sealed, then put in all new insulation, that gets me to at least r-30.

Is it acceptable method:

1. clean attic of visible bugs, droppings etc.
2. Remove plywood/osb from the floors
3. Remove existing blown in and batt insulation
4. Clean area again
5. Seal between floors, walls where one of the attics butts against the second floor rooms
6. Add faced batt insulation r-19 up to r-23 (attic floor joists are only 2x6) and add 2 inches of foam board insulation directly over joists
7. Re-insulate the air supply and vents for the attic over the second floor
8. Screw back in the mix of plywood and osb panels with longer screws

https://imgur.com/a/RODUAJP Link has photos of existing attics, and my plan. Not really visible is the filth.