Drywall – what order should I be replacing floor and drywall in

DriCore is a subflooring that is specifically designed for light or occasional moisture. The portion of the product that touches the floor is all plastic and it lifts the upper portion more than 1/2 inch away from the concrete floor. The joints are fairly tight (although not actually sealed). It is intended to allow water to accumulate in the open spaces under the plastic waffling and drain or seep away without reaching the upper layer.

The particle board that makes up the surface is impregnated with resin and is meant to be fairly impervious to moisture. If you have an actual flood that occurs which is high enough to reach and damage the surface, you have much bigger problems.

You said the subfloor is particle board, so if there's some kind of isolation under that you don't need more barriers.

Attaching your floor to the subfloor depends on what kind of floor that is. If it's floating floor, it needs to float, so no gluing at all, and you need some kind of padding to level out the floor. Generally floating floors are tongue/groove or click install.

And if it's kind of parquet you have to glue it to the subfloor, because the grip of nails to particle board is very weak.