Ok, now I see there are actually 2 videos you are talking about but only one link in your first post. Two totally separate questions....
Suet is nothing more than beef fat, usually from the kidney area near the tenderloin. Leaf lard is pork fat from the same area of the pig. Suet will also completely render as there is no connective tissue in it. Suet would normally cook/render quicker than other fats and can also spoil. There are a good number of sausage recipes out there that call for Suet in the mix. Looks like it's the old school way from the 18th century and early 19th century. I've never personally used it in sausage making though.
As to the dehydrator temp. If you are going to heat it to 180* you are not dehydrating the meat, you are cooking it. Might as well do it in a regular smoker and get some smoke flavor while you are at it. You will need air exchanges in a smoker though to get the moisture laden air/smoke out of the cabinet to facilitate the drying process. Once you get over about 170'ish you will start to render any fat that is in the meat strips out so the cut of meat matters. Dehydrating is the drying of a product to remove the moisture. She is talking about cooking jerky in that video when she insists the "dehydrator" must be 180*. You might need to go over 180* with an uncured meat to kill nastys, but that's why we use cures in jerky, snack sticks and most sausage.
Make sure to read any of NEPAS's jerky and sausage posts. He is one of the ancient ninja masters of the dried and smoked meats around here. He has also posted a lot of proven recipes you may want to take a look at. Same for SolorYellow, Pops, Cougar, and quite a few others here.