Great summary. This is exactly what I found in my research too. I suppose there is no "best" option as it depends on your needs. For reference, I have a 2012 535i with CIC Pro Nav. I'll likely be getting the Unichip once wireless CarPlay is available.
Option 1 - I don't know where the post is but they seem to have confirmed that full screen support is not coming. Using the factory mic is a big plus, but I hate the fact that it's not full screen.
Option 2 - My preferred option, as long as (fingers crossed) it works. I was unable to find any details about a wireless option with them. For all we know, coming soon could be Q4 2019
Option 3 - My second choice. However, I see screen mirroring as largely useless. I would rarely use it, much less for Navigation. As I understand it, you'd need to keep your phone screen on and rotated to the landscape view.
Option 4 - Personally I would not go anywhere near this. Besides the lack of CarPlay, traffic and Push to Car, even CIC iDrive is good.
Option 5 - Too expensive when there are other options.