"So I've read that having a higher metabolism will keep you warmer. I've also read that having more body fat will keep you warmer."
To be clear, only fat "keeps" you warm. The metabolic process "makes" you warm. A proper ratio between them is ideal.
"I'm pitting them against each other in my head because when my body fat % is lower, my metabolism seems to work much faster."
I'd venture that the opposite is true. Once you increase your metabolic rate, you burn off excess fat.
It seems that strength training burns calories for longer, keeping your core temp higher for longer (more muscle mass recovery = more heat generators), while cardio training burns calories faster, for more immediate weight loss, but shorter recovery times, leading to lower resting heart rates (heart muscle training only) and cooler core temps from less muscle mass compounded by less body fat, and with more efficient (slower) circulation from a stronger heart.
I'd think it would stand to reason that less cardio and more strength training would increase core temp regulation better than cardio alone burning off ding-dongs and ho-ho's as fast as you can eat them.