Wow, seems like you've done a lot of work here since I commented last time.
Anyway, some thoughts on transport & communication:
In the civil sector, I would expect three developments after destruction of the HPG network to take place.
A) Every trading company begins to trade in information. This sounds obvious, but is very important. Since you can transport practically indifferent amounts of data aboard of a jumpship/dropship without cutting back on the cargo you can transport, the information transfer between world may be slower, but the frequency of information "packages" arriving is only limited by the general jumpship traffic. This also makes sending data from one world to the next not more expensive (or probably even cheaper) than with the HPG.
Since time can be very important for some people (military, business, etc.), there could be two different kinds of sending data.
First, on a data disk (or crystal or what ever else), transported by dropship from one planet to the next (the slowest & cheapest form).
Second, transmitting the data via radio to the jumpship and from the jumpship via radio to the target planet once in system. This would be several days to a couple of weeks faster than the first method and probably more expensive, since the amount of data you can transmit via radio while recharging and waiting for new dropships is limited.
B) Since data transfer and cargo shipping is the same business without HPG, ComStar would probably be in on it. This means, ComStar is in direct competition with every other shipping company out there, since they would operate there own fleet of jumpships. If a shipping company has a monopoly in a nation or sector of space, this could seriously hamper ComStars effort of spreading there and rebuilding the HPG network in those parts of the Inner Sphere.
Now, for the military implications:
Since the lack of HPGs means, that a central authority would have even less means to coordinate with forces away from home (distant garrison forces or invasion/raiding forces). This would mean, that the commanders on the scene would have greater autonomy in leading their forces. I could see this developing in two different directions:
A) The military high command trusts the commander enough or forces away from home are so far away from any form of control, that the commander in charge can do what ever he or she wants or thinks is right. A commander could only be judged/punished for his or her actions after returning home. If the commander thinks, he or she has failed their nations, he or she could decide to go rouge instead of returning home. Such a system would only be effective, when the nation does not punish every form failure (like retreating from a superior force).
B) On the other hand, when the ruler or military highcommand does not trust their commanders, they could always use some form of secret service to control them. If there are several spies/assassins embedded in every force away from home, commanders would be very motivated to reach their goals and very paranoid towards their own forces and could lead to infighting between secret service and army. While this would seriously hamper the performance of the military, it would give the rulers or the highcommand a greater feeling of control and would be, in my opinion, a logical model for the more autocratic nations (Draconis Combine or Capellan Confederation).