Game Pass Ultimate: Share across 1 PC and 1 console (Yet another Game Pass Sharing question)

Hello, I have read several contradicting answers in this forum regarding sharing a Game Pass subscription within the family. My setup is also slightly different from previous questions, so here goes:

My father is planning on buying an Xbox soon and get the Game Pass Ultimate. He doesn't have a capable gaming PC, which I do, meanwhile I don't have my own console. Additionally I have a previously purchased game on my Xbox account and I have purchased another
application on the Microsoft Store for my PC. My father doesn't have an Xbox profile as of yet.

Since we both would profit from completely separate aspects of the Game Pass Ultimate, and apparently sharing a Game Pass with family members is generally a thing, I am very unsure about how to do this using only one subscription. Other people have asked
about sharing across 2 consoles and sometimes 2 PCs, for my case it is only one console and one PC, does this make it any easier?

I consider the following possibilities:

A. I subscribe to the Game Pass, sign in to his Xbox and set it as my home console. Then I sign out and he signs in. Am I correct in assuming he will be able to access all the games on the Game Pass without me taking any further action?
If so, does he also get the included Gold membership to be able to play online? I wouldn't be using it on PC for obvious reasons. If this is not the case, B is not an option, him being able to use the Gold membership is important. If it is possible, is this
the best option then? Since sharing Game Pass benefits on Xbox seems to be easier than doing so with a PC, according to other threads.

B. My father subscribes to the Game Pass and sets up the console for him. Since the option to add a second non-educational-or-work account to the Microsoft Store on PC is gone (removed?), I would have to log out of the Store and have him
log in using his credentials. From there I see two possibilities:

(1) I stay logged into his account on the store. What happens to my purchases, do they still work? Will I still be able to use my own Xbox profile to play? (I assume not)

(2) I download the games I want to play and log back in to my own account. This means every time I want to download something else, I need his credentials again, correct? Are there other times where I would need him to log in using his account?
Does this work reliably, as in, is it intended to be able to play the games on my Xbox account even though his account has been signed out from the store again? In case option A. doesn't work as required, is this the best option, even though I may have to
ask for him to log in every now and then?

C. If all else fails, since my father doesn't have an Xbox profile yet, I could log into his console and leave my account logged in. This appears to be the easiest option, however resulting in his progress being saved on my profile and I
assume that as soon as we try to play games which log in using an Xbox account together, this method wouldn't work. What about playing different games at the same time? Can a single account play different games on different machines at the same?

For that matter, can two different accounts using a single Game Pass (as with method A or B) play either
two separate games which are included in the Game Pass simultaneously, and can they play the
same title on different platforms at the same time?

Basically, what is the best option for us, and will there be any side effects as my questions within each option suggest? I hope someone can clear this up and that there is a good way to do this. Thank you for reading my lengthy train of thought.

:)