I adapted SSDT-TB3 Z270.aml for my Z170 with builtin TB3. When I have a look in ioreg, I see lots of extra PCI bridge stuff and no proper TB... I also see extra PCI devices(with the wrong names) in "About This Mac..."
Hot swap doesn't work, when I unplug my TB3 adapter my USB-C devices on the other (combo) port get kicked of too. Replugging doesn't do a thing.
Attached devices survive sleep, and I can shut my hack down without reboot.