If you are gluten-free, use wheat-free tamari in place of the soy sauce. If you don’t have rice wine vinegar, substitute apple cider vinegar in its place. Fish sauce adds a wonderful umami background flavor and I just discovered Red Boat fish sauce, slow-aged in Vietnam from anchovies which is more expensive than regular fish sauce but is pretty lovely stuff. (I bought it at Whole Foods, but it’s also available on Amazon.) You can get standard fish sauce in most Asian markets. If you don’t want to use fish sauce, well then, just leave it out. As for the chicken, if you can’t get thighs, feel free to use whole chicken, cut up, or other parts. I gave the approximate weight so you can use that amount for the quantity of marinade given. Although I don’t have one, you could probably cook these off on the grill. I might suggest reducing the sauce a bit and basting the chicken with the sauce while you’re grilling it.