there's a bit of a consensus that you're going to want to marinade first, then smoke.
couple reasons for -
one, the marinade can (and will) wash some of your smoke flavor out - not good. two - smoking, even cold smoking, changes the surface proteins of the meat, making it more difficult for things like marinades or seasonings to penetrate. so you'll wind up with both under-marinated and under-smoked meat going into the
dehydrator.
another one would be food safety - depending on how long you're cold smoking, your meat (unmarinated) will be in the danger zone for pathogens for too long (40f-140f). Whereas, if you marinade first, you're at least going to be adding salt and maybe sugar, which'll make the meat less hospitable to stuff that wants to grow on it. (and you'll have an even greater measure of safety if you're nitrate curing - prague powder, etc)
I speak from personal experience.. I had that idea before, and I tinkered for a while trying to get it right, and did some research into the why.
here's what I found works - vinegar soak the meat strips for about 30 minutes (step from biltong making that helps eliminate surface pathogens), then into the marinade for the allotted time in the fridge (usually overnight) take out of marinade, dry in fridge on rack for 12-24 hours (pellicle formation - lets you capture a solid smoke flavor) into the smoker for several hours (depending on wood, temperature, intensity of flavor, etc) and then, if you're dehydrating, you can either 'semi-cook' (
dehydrator at 165F) your jerky.. or if you've done well with curing and smoking, you can cool dehydrate at about 100F (which turns out a better product)
curing and cooking to 165 is an industrial regulation to ensure it's shelf stable for as long as possible - if you're nervous about it, then by all means cook it with the
dehydrator. (no sarcasm, I promise)
it'll still be good. I personally trust the cure that I use and the hours of smoke I lay on to make it totally uninviting to the microbial nasties. that and because jerky and other stuff goes so fast around me, it never really has time to think about going bad.