So I’ve heard before that BFA is worth 1/50 building stats, is there any similar rules for other bonus stats like furns, charms, or equipment? Also is there any formula ppl just use to add all of these things up with?
Stats from furniture, charms, equipment, and allies all add to "building stats" (aka raw stats) on your profile. Your bonus to allies stats (which are what you see on other people's profiles) are equal to 1/50th (or 2%) of your raw stats upper cap (i.e. they do not decrease with troop levels, unless it's a % based boost). So, in terms of bta stats, all those boosts are in fact worth 1/50th.