Awesome, thank you man. TBH I was worried this would be a bit of a challenge in every regard, but it sounds pretty straightforward honestly. I'm pretty confident the local shop I use for things I can't/won't/don't want to do could definitely accomplish the vast majority of this for me.
5. you need to figure out codding of CAS, unfortunately it seems without professional software/hardware like bmw explorer and KTAG its not possible to do, but i cant confirm 100% as i'm not professional on this area.
Is your shop able to do step 5?