I would also recommend the 3 zone Climate and the Parking heater. This is our first Beach with the parking heater and me and my girls slept in it last weekend. We would never of done that in either of the previous ones, not at this time of the year.
The extra side window (with fly screens) would help for better ventilation during the warmer nights. We have holidayed in France for the last 5 years and I’ve always wanted greater airflow downstairs .
We’ve now got the Art Velours seats and it lifts the interior massively. The van feels more special, like a Caravelle, and to me feels more suitable for a van with this price tag! I really love it.
Heated front seats? A must to me, really missed these on our 2nd van.
From your list, I haven’t got the following:
Stronger battery
Tow bar
Parking Sensors (i just use the rear camera)
Mudflaps
TPMS
i would 100% keep the Comfort mattress, panoramic roof and rear camera that is on your list.
oh... and I’d definitely recommend the LED headlights!