2-series does in fact allow you to add NVX devices, though I would be careful about scale...Seems that your system is pretty small..
regarding SMW Programming/Routing:
I have always just used the StreamLocation serial in/outs from the NVX device symbols. You don't need to do any subscribing, which is only needed (I think) when you're using the web browser though I don't even know that its needed for that...
In SMW, set up a programmatic serial matrix logic and route the 'StreamLocation_F' output signals from the encoder device symbols to the 'StreamLocation' input signals on the decoder device symbols.
If you're using any of the 300-series endpoints, you'll need to initialize the Video Source Analog inputs on the Decoders for select the stream input instead of the local HDMI inputs, on the 300-series Encoders, you'll use the Video Source analog input to select the input HDMI source desired...
That's all that's needed for routing, and it is very scalable...
