Great questions! Let's see if we can help here:
1. The Trios are not compatible with MB Sync out of the box. The Trios come with a 5 port digital controller designed for TT RGB Plus only. If you want to use the Trios with MB Sync, you would need a motherboard with a 5v addressable header and our TT Sync controller. You can find the TT Sync controller here: https://www.thermaltakeusa.com/products-model.aspx?id=C_00003143
2. All of our digital controllers come with a "Y" USB Splitter cable, as USB 2.0 allows the use of 2 cables rather than a single cable. The bridging cable will allow direct connection to 2 controllers as needed. Use the single cable if you only have 1 controller, or the bridging cable if you have 2 controllers.
3. Each controller will require power. This is used to power fans, LED strips, and other RGB PLUS devices. The controller will need power, even if you are plugging in one fan or device.
And to answer your question on the Maximus Formula XI, each header would support a max of 120 LEDs. This means that for 6 Trio fans, you would need 2 5v headers and 2 TT Sync controllers. We will be testing this in-house for confirmation, allow us a few days to get our test bench set up and have the fans tested.