Welcome Jughead028
1. More than likely will be a control arm that is bad.
The e53 does have a decent amount of + camber, but shouldn't cause that much wear.
Could be either camber or toe is out of adjustment. Both can be adjusted on the inside part of the wheel carrier where it connects to the subframe.
2. Agreed BMW is usually optimistic on this. As long as the factory tire size is correct, that's just the way it'll be.
3. Looks like the fill plug is on the side of the tranny just above the pan.
Be aware that the drain plug might have a plastic cover on it to protect it.
On my 2006 4.4i it was black plastic which made it difficult to notice.
This gives a full teardown of the tranny.
https://xoutpost.com/bmw-sav-forums/...-teardown.html