Does anyone know if its possible to activate features like hill-start assist, deflation detection and overhead ambient lighting?
I'm pretty sure that most of these features rely on hardware that is already there like ABS and ESP.
Yes, some if not all are just software options. For example deflation detect just uses the existing abs pulses to sense the wheels are rotating at different speeds. Trouble is you need the equipment to turn the options on. You need to find a very friendly Ford mechanic and bung him a few beers or maybe a specialist will have the equipment. Another option is to look at some software called UCDS which is Ford specific and may be able to turn these options on.
You may struggle with ambient lighting as this requires wiring and lights in various places (overhead, interior handles, foot well, and center cupholder from memory).