Is the Content Reader Space Exploration friendly? That is, does it recognize when networks exist on a different surface, and only output data for the current surface or does it output all data for all LTN stops on all planets?

It doesn't take surface into consideration, all same networks on different surfaces are summed up.

Any plans to make it surface aware at some point, or not on the roadmap?

No.
Now that I think about it, I prefer reading Martian Network 4 and Venusian Network 8 from Earth.

Hehe cool, just wanted to make sure before I started reworking everything to make it work. Yeah, with it reading off-planet networks, I'll just need to assign each planet to its own network. Then I likely won't even need to use the SE signal transmitter and receiver.