So you may see ONE speed displayed by L-Connect 2 for each of the ports, but not more. I suspect that, in a manner similar to what a mobo port does, each of those Controller output ports can deal with only ONE fan's speed.

If I understand correctly, the Unihub actually has four Controllers in one box, each creating a potential Group of up to four fans connected to one of the Unihub's four ports. That may be able to show you some fan speeds. Your Unihub Controller has a cable to a mobo USB2 header for the communication function, and you should be running the Lian Li utility L-Connect 2. But then there also must be some communication system and some software utility running on the computer that can retrieve that info from the Controller and display it for you. For CONTROLLERS with some 'smarts' of their own, it is possible (depends entirely on the features designed into that Controller) that it may have its own means of counting pulses from a fan plugged into one of the outputs. If the fan is plugged in anywhere else (and not forwarded by that grouping device) its speed cannot be 'seen'. Next, this means that the only way your mobo can tell you any fan's speed is if the fan IS plugged into a fan header to receive that speed signal. The ones ignored will never be shown or monitored for failure. So any Splitter, Hub, or external Controller that connects several fans to ONE host header will send back to that header the speed signal from only one of its fans, and ignore all the rest. Now, at the header, it can deal with the speed pulses signal coming in from ONE fan only - two or more superimposed causes huge confusion, false readings, and many errors. It does NOT use that info for its speed control functions, but it does monitor that for failure - that is, no speed signal - so it can warn you when that happens. The header counts those to display fan speed. Start with: every fan generates a speed signal consisting of a series of 5 VDC pulses, 2 per revolution, that it sends back to a mobo header on Pin #3 of the connector / header.

Lian li uni hub