The only alternative to FW is if you have a thunderbolt port, and utilize the FW to Thunderbolt adapter. If the PC is a desktop, and you have slots available, you can add a PCI/PCIe FW card. On a laptop there are expresscard FW adapters available if you have an expresscard slot.
There are no motorized faders on the Studio Live mixers. The CS18 is the first presonus product with motorized faders, and is designed as a dual purpose control surface for the RM mixers and Studio One.