1. It's on the thread. There are some questions about one or may be two that don't work on Formentor's believed to be associated with the firmware. Unlike other boards it isn't a cut and paste list from other VAG cars.
2. No, they aren't that bright.
3. It can be seen but again they wouldn't be looking for it unless it broke something.
4. No I'd say.
Suggest you keep well clear of the micropayment credit apps. They are designed to make it easy but if they aren't correct you can't wind back what they did. There are followers of these since Obdeleven have provided the tools in their enhanced package which essentially allows crowd sourcing of mods but without proper QA using may mess up the cars coding. If you don't have the Pro license you can't attempt to untangle what they did. They are in Obdeleven to challenge Caristas market for that type of app but both fall foul of the same issue.
I have always kept well clear of performance mods. I dont reckon there aren't any on the thread so far.
With mods it's a question of looking at what is published for the car model, then looking at mods for the associated platform, Leon 4, Golf 8 across boards. Specific lighting arrangements or other kit won't be the same, core things will be. On the specific you are on your own until the user community has worked out the mod. On the rear lights one that has been done on the thread as an example. German tends to be used but sometimes translated as the terms within the mods. When you are in uncharted mods if you don't know German you are translating German words, fun. You can take a freeze picture of the Obdeleven screen atleast in Android, feed that image into Google translate app, rub on the word and see what it's saying. Where German speakers have the edge on uncharted mods.
. 
. In analogue form it's a test swing, but for digital no use so VAG didn't implement it.
. You need a styled trailer to match....
.
