Precept Mods/Order Equip

I was researching the subject and I came across that this system works for sentinels. But I had a doubt, the companions (vulpa, kavat, kubrow) also have precepts mods, does this system work the same way? And for primary, secondary and melee weapons, is there an order to equip, as an exception to create elements?

(Precepts mods have the polarity " [- ", and the order makes a difference when activating sentinels abilities)