Yes, it is possible to use the FS Traffic models and liveries with the simulator's Real-Time Traffic, but the model matching is broken in the simulator at the moment so the correct liveries likely won't show for each airline. For example, an easyJet flight may show as an A320 operated by a Chinese airline rather than an easyJet liveried A320.
The steps required to use FS Traffic with MSFS Live Traffic is covered on Page 33 of the FS Traffic manual: https://downloads.justflight.com/products/JFF003616/FSTraffic_MSFS_manual.pdf
For now though, we would recommend using the standard FS Traffic Offline Schedules if you want to see the correct aircraft models and liveries.
Mark - Just Flight