Done.
Now, answering your questions:
Ok, about the USB, you can create it manually. General structure is:
- .lst files are always placed in the root, they are just text files
- packages are placed compressed (.tar.gz extension) under a folder called SyncMyRide
And that’s about it, it’s described as well in the manual guide 's instructions.
Syn3updater only works for 3.3+ versions, so you need to manually create the upgrade USB.
You can take this post as reference → 2016 Mustang Sync3 1.0 updated to 3.0 and no Apple Carplay! - #10 by SaNdMaN
Also, since your vehicle is from 2016 you may need to update your USB HUB. Take a look at this post → Media Hub, CarPlay Compatible - 2015-2020 Ford/Lincoln - SYNC 3
It’s recommended for you to make sure CP works BEFORE moving to 3.4.
Also, it’s mandatory for you to confirm the APIM model by executing the interrogator log (can be created manually) or by entering the bezel diagnostics from the unit itself ot see which part number the car has.