Garage Floor Raise Questions...

I am looking to raise a floor in my house (was a garage originally) to be level with the rest of my house. In the 60s it was used as a garage and was converted to living space in the 70s or 80s. However, they never raised the existing garage floor so it is kind of funky since there is a four inch or more drop between rooms.

-FYI the garage floor is a suspended concrete floor and well above grade so moisture should never be an issue like it could in a basement garage.

1. Laying a moisture barrier (if I should given my situation).
2. Raising the floor with treated 2x6's that are ripped to the correct slope (fastened via block and tapcons).
3. Insulating the floor (with fiberglass or polystyrene if I have too.)
4. Laying the subfloor.

Should I utilize a moisture barrier?
Would fiberglass insulation be okay?
Any other thoughts or suggestions?

Thanks all.

You are not on the ground so why would there be moisture coming up through the concrete, and the same question regarding using treated lumber. Both are only required when installing over concrete on "grade". As far as securing the 2x6's construction adhesive will keep them in place until the floor is installed, and once that is done the weight will keep them in place. What is under the concrete will determine with it needs insulation or not. Number 4, installing the subfloor, is correct, however.