>>328628916
You can slap all 3 dongles in 1 usb hub if lucky(sometimes trackers spazz out if you do it) and still then, you can always use a hub with the dongle extension cables. I would not say the super dongle is a good enough argument at this time.
>>328629129
Smaller, yes, the rest is speculation as no non Tundra info is out.
>>328629341
Not for FBT really, the Vive ones are designed to be generic, while Tundra have FBT as the main use case.