I have to walk back some of that. I’m at a ‘01 wagon at the pick-n-pull and it’s different from my ‘98. The trim across the top of the hatch opening doesn’t have to come off, neither do the seatbelt anchors. The side trim looks like two pieces (and should be!) but the pillar pieces are inseparably fused to the upper pieces. There are T-20(?) head screws holding the roller blind track to the pillar that look like they have to come off.

You might have sufficient access just lowering the side piece. There’s a nylon strap not in my ‘98 that limits how much you can move the side trim. Looks like you can remove the aft attachment of the nylon strap. The forward attachment is deeper under the headliner.

Mind the side airbag cylinder!

Sixto
98 E320s sedan and wagon
02 C320 wagon