Can you use a single thunderbolt port to power two extended displays in clamshell mode?
I think you've confused Thunderbolt and USB-C.
The problems with these &quot;display splitters&quot; that work as &quot;ABC&quot; in Windows and &quot;ABB&quot; in Mac is that they're USB-C cables. They require demux functionality in software that macOS doesn't have currently.
However if you have an actual Thunderbolt cable then it is fully possible to do &quot;ABC&quot; with a single cable.
The MacBook Pro's lid being open or closed makes no difference at all in this.