Frostfall Armor Not Workingl
With SKSE64, Frostfall uses a different method to look up warmth and coverage values on armor. These SKSE methods depend on StorageUtil functions of PapyrusUtil, and without them, zero warmth. Installing PapyrusUtil SE to your game will get armor warmth working again with SKSE64. When SKSE64 updates with new version, also check PapyrusUtil SE for a new version.
Frostfall Armor Not Workingl
Start the game using the SKSE64 loader and load a character (preferably un-modded save). Check to see if your armor has warmth and that MCM Frostfall and Campfire appear normal. When starting up Frostfall, it may take several minutes (depending on how many supported armor mods you have) before Frostfall finishes building the armor table and saves it to your SKSE plugins FrostfallData folder.
Further integrated mechanics include Warmth and Coverage ratings for armor to determine how much it insulates against cold and water, a power to sense the weather and be warned of incoming storms, and an ability to craft some basic gear in the wild like fur armor, makeshift bows, arrows, and hatchets, and more.
Apparently, the reason for losing Stamina constantly wasn't a mod conflict or anything, it was my own stupidity. I didn't know that wearing Heavy armor in Requiem caused a Stamina drain if you did not spend any perks on it. I was wearing a Heavy helmet. Removing that got rid of the Stamina drain and it's all good now!
The aim of Frostfall is to make Skyrim more realistic by allowing the Dragonborn to die of hypothermia in the arctic regions of the province. The Dragonborn must wear warm clothing (such as fur armor), build campfires, seek shelter and keep dry to survive. There are three preset difficulties, the hardest of which prevents fast travel. All aspects of this mod can be tweaked individually with the Survival Settings power (users of SkyUI 4.1 or above can make changes through the Mod Configuration Menu).
Frostfall also has a mechanic called W.E.A.R, which causes the Dragonborn's resistance to exposure to be directly affected by the type of clothing they wear. For example, equipping full fur armor (including head gear) will give them 100% exposure resistance, as long as it is the fur armor texture that has sleeves and a shirt (not the skirt version). Additionally, cloaks from the Cloaks of Skyrim mod work in tandem with Frostfall, keeping the Dragonborn warm and/or dry, depending on the cloak's material, as well as increasing resistance to exposure.
Frostfall has many crafting and gathering features. One of them is gathering deadwood, which allows the Dragonborn to build a fire (an essential for survival). If they have a woodcutter's axe, they can harvest firewood (it requires less firewood to start a fire than deadwood), which adds wear to the axe. (Firewood collected by using a wood chopping block with the same axe does not cause wear). Firewood can be used to build a tanning rack, which the Dragonborn can use to craft fur armor, tents, and other things to help them survive Skyrim's often harsh climate.