Hello royber.
Our guys answered about Ds:
1) YES, this CVT-ECU supports Ds mode
2) If you won't use ASC OFF switch in future, you can use it for Ds. But you should make an additional circuit because this knob don't have a fixed "ON" mode
circuit #1 - use relays:
(used 2 diodes type 1N4007, 1N4001 etc)
another circuit #2:
3-4) of course, you can use any hidden connectors. One of our smart guys modified 2WD/4WD/Lock switch:
https://www.out-club.ru/board/showthread.php?p=764659#post764659 and Ds mode is activate by pressing it down.
Also you can use standard knob like ASC OFF but with two fixed ON-ON position (switch) - no any circuits needed.
PS: please give us a links where you had modified cabin temperature sensor. I can't say that AC works bad, but we like to DIY. Did you hear about the HEAT that now in Russia about 2 months? Outlander's AC works fine in these very severe conditions.