I would assume that disabling the fog lights in VCDS would also disable the bulb monitoring for fog lights. Probably they do this same configuration on the factory (with their own programmers/testers, of course) depending on whether the vehicle was supposed to be equipped with fog lights or not - otherwise it wouldn't make any sense... But after all, this is pure speculation.
However, I don't know what would happen if you decided to activate the fog lights using the light switch while they are disabled... Perhaps nothing, or perhaps some mysterious fault code in the fault scan logs... :-k
According to the Touareg wiring diagram, J519 Onboard supply control unit fitting location seems to be: "On left under dash panel, near centre console". I'm wondering how many dash panel parts one has to remove in order to get access to this module...
There are two wires going to the fog light bulbs from this control module.
Left bulb: white/yellow wire from 6-pin white connector, right bulb: black wire from 6-pin brown connector.
So if one would disable the fog lights via VCDS, then the wires would probably be free for supplying clean switched +12V to suitable LED modules.
Any utilization of this info with one's own risk, goes without saying...
Now, the biggest problem seems to be finding such EU type-approved DRL LED modules that would be pretty much drop-in replacements for the Touareg fog light assemblies!