Disclaimer: I could be wrong, but this is my take on all of that.
Lightsquared was going to convert Satellite spectrum for terrestrial and satellite use for end users. They would supplement the terrestrial network with satellite coverage. I believe all the backhaul for the network was going to be fiber/microwave. That is why they were planning on teaming with Sprint.
Dish is in a similar situation. They are proposing to convert satellite spectrum for terrestrial network also, but I have no idea if they are going to supplement with satellite coverage.
Also, after researching more, satellite backhaul can provide the bandwidth for COW and SatCOLT, but would not be optimal for voice communications. There would be some issues with delays, but everything else would be fine.