Can the Legacy base be interconnected to DCS like the TMCC Command base?
Yes but you will need the new MTH cable to connect them.
What features will Legacy engines lose if run via DCS or Conventional?
200 speed steps, quilling whistle, train brake to name a few.
Can the Legacy base be purchased separately?
No, but many folks want just the Cab2 so you may be able to sell that on the after market scene. But you still won't be able to access the above features without the Cab2.
Marty, thanks
The 200 speed steps would be nice to have.
I have a 3rd Rail E7 coming, but can't seem to find a TMCC Command Base, no telling what features I'll miss out on running it Conventional.