Yes, you need to pull a ground wire from the house panel out to the sub panel, I don't have my cheat book in front of me but pretty sure it would be a #8 copper or #6 aluminum depending on what you run for your phase conductors. So you will need (3) full size conductors ( (2) "hot" conductors, and (1) neutral) then the ground can be reduced. At the sub panel you need a neutral bar (for all the "white" wires) and a separate ground bar (green wires). The neutral bar needs to float, i.e. not be bonded or directly attached to the panel enclosure or ground bar. The ground bar will be tied directly to the can. Most newer panels will have a jumper or "green screw" that bonds the neutral bar to the panel, that will need to be removed for a sub panel.
You need ONE ground rod at the sub-panel, not two. Two is for the main service. 5/8" x 8' if all you need, it can even be one of the cheaper galvanized ones, for a 100A sub panel a #8 copper to the ground rod should be all you need.
Also pretty sure, by code, you do not need separation between comm and power, that's usually a utility or engineers spec. Never hurts but for residential use you should never have an issue, especially if you use shielded comm wire. I would have to look it up to be 100% certain, it might be an the WAC but not the NEC. I usually don't think much of is as most of what I deal with is spec'd, utility or over-engineered to the n'th degree.