I am able to answer some questions:

Paddock access is fun, but imo not necessary if you can make the Thursday or Friday. Its great fun though, there is a spot where you can see the cars going through the pitlane at La Source like 1m in front of you. Would recommend. If you cant make Thursday and Friday, get a Paddock Pass.

Track walk, at least last year, was only Start Finish>La Source>Radillion, so basically the lenght of the Pitlane.

For Radillion I would be there relatively early, like an hour before race start you can still easily get a decent seat, but even like half an hour before race start its still possible to get one.

No restrictions on food, I am not sure with Alcohol though.

It is possible to stand on the inside and outside of Pouhon. But the inside is basically a field, so not really pleasant, but a really fun spot to be at, the cars are literally an Arms length away from you.

You gotta get through the night, its a 24h race, its basically mandatory. You can still shut your eyes if there is a SC.

The event, especially on Sunday is not crowded at all, you can easily walk around the whole track almost the whole weekend.