@ReaGeorge
Working my way through your list, next the oil filler on top of the engine.
Do not think it should be rock solid, the design will always give some give but it is important to have a good seal else I think it wil throw up faults. It might well be okay but if you want to try and improve matters ...
First have a gentle wiggle of the cap to assess movement and plant fresh in your memory to compare with the after "repair".
Carefully ease out the ribbed spigot on the left of the filler to disconnect the pipe that runs over the the top of the engine. Now twist the filler a fraction of a turn and lift off the engine. Turn upside down and inspect how it gets its grip. You will see two small 'fingers' of sprung steel strips that pull the filler down onto top of the engine to make the seal. As I see it use two pairs of pliers to try and flatten (squash to filler) these 'fingers'. Replace the lot and assess if it is better.
Hope that makes sense, just trying to help.
Andy
PS. They are about £30 new from Crewe Audi on here but you are long way from replacing. Before that the best thing is compare if possible with another FSI and seek opinion of owner or garage. If a scan throws up a code and a loose filler might be the cause of it after other possible causes have been checked or it is visibly leaking oil and the above does not work then replace.