In my experience, if you do not remove the fat before dehydrating, you can end up with three issues later. 1) The fat seems to inhibit the drying process. This is not very surprising since a layer of fat on the meat will block moisture movement out of the meat. 2) I found that meat that was dehydrated with the fat became rancid within a week, and had such a foul smell that it was not edible. 3) Meat that is dehydrated with the fat is much harder to rehydrate. Again, I think this is due to the layer of fat inhibiting the movement of water, this time into the meat.
I brown my meat and then quickly rinse it in hot water. The resulting product dehydrates readily. When I cook hamburger helper with it, I don't even bother to soak it first; it goes in with the cooking water and everything is cooked at once. The resulting product is hard for me to distinguish from that made with fresh meat. Regarding adding bread crumbs: I would consider that very carefully. You would be adding a material that is much more likely to absorb moisture in storage that the meat on its own would. In addition, you are providing an inviting substrate for mold and other interesting things to grow. Dry meat on its own is as attractive a growth medium for bacteria and mold.