Now to answer your questions Lija.
for hissers you want to follow the same feeding, temps, and husbandry as you would dubia. If you would like I will send you my detailed self made care sheet. the difference is hissers get twice the size as dubia and they can climb smooth surfaces which a thin layer of oil or vasiline will take care of that problem. And dubia males have wings that only allow them to flutter.
another difference is dubia can handle a wider range of humidity. I personnally have not proven this however this is word on the street per say, and i would follow it until further information has been provide with substantial facts.
Substrate can be used and you will have great success but you may also use no substrate for they create their own, its called frass. egg crates make much more surface spaces which is good if you have large numbers. If you have a few dozen branches and bark will suffice just fine. Temps, humidity, surface space, darkness and diet are the main factors for both species and they are the same.
The reason for all this conflicting information is just as Jeff said. Roaches can thrive in a various environements and will eat almost anything. some enviornments are better than others. Just as foods. For example i fed my dubia a staple on dog biscuits and dog food and mangaged to raise my population up to 40,000 strong. But when i started feeding them nothing but plant matter their death count suggnificantly decreased and breeding increased by more then 400 percent. look up my thread in the feeder section for more detail.
Roaches have been one of the most successful species on earth for good reasons.