Been wondering about inhabiting spirits

Hello Twin Peaks lover friends!

I'm watching the great show for the 4th time now, I am at s02e11 right now. However, I've seen FWWM and The Return only twice and I've read the 4 books (Laura's and Dale's diaries and Frost's two green books) just once.

My thoughts got stuck on the mind/soul inhabiting spirits like Bob and Mike.

I have been wondering why spirits like Mike is a permanent occupant of Gerard. I don't remember if Mike was absent in real life after he sniffed out Bob in the Great Northern. While Bob had at least 2 in the show (Leland and Mr C). (Btw how did the small paper with one of the letters in ROBERTSON get under the nail of Ronette in the hospital?)

I also don't get why Mike has the same appearance in the dreams and in the Black Lodge as in real life in Gerard's body, but Bob has no such a physical body.

I'm also struggling to solve why Mike can appear in the Black lodge, namely he turned to a good spirit at last (cut down his left arm). My understanding so far was that The Arm (dwarf) has somehow arose from Mike's "evil" left arm. The dwarf is even so neither positive nor negative. Sometimes helps Cooper, sometimes helps Bob.

Who do you think in the show is yet such a host person in the show?

• obvious: Leland and Cooper --> Bob, Mike --> Gerard

• the old waiter with milk --> the giant

• the Log Lady? How could she deliver such important information?

• Mrs. Palmer --> Judy?

• Mrs. Tremond and Pierre? Idk whether they are good or evil spirits, but in fact, they both had the same body in the real life and in spirit world (convinience store). However, Pierre seems to like garmonbozia, which as far I got is consumed by evil spirits (pain and sorrow).

Sorry for the long and discursive thoughts 🥹...