There are some general points to cover about lithium iron batteries in the cold and then some specific points about Coguzzi's question.
-- Most lithium iron installations are inside the heated camper, for obvious reasons. If you cannot do this (as was the case with my Tiger) then you have to look at some form of insulated box and heaters may indeed be a necessity in regular use.
-- Most of us don't let the interior of our camper drop below 0C because we don't like cold or frozen pipes. So, most of the time, when camping, your batteries will be fine.
-- When not using the camper, you will either have to winterize, or keep the interior above 0C. I live south of Quebec and it doesn't usually get as cold or stay cold as long, so, during the shoulder months, I drain the tanks, remove the water filter, and use the Dual Top's automatic frost protection setting. I also have an electric space heater which I can use on the inverter or shore power - the latter being preferable.
If you do let the batteries drop below freezing, then they must be warmed before recharging. Again, some assumptions:
-- You will not let the camper batteries drop below 50% before parking. (N.B. with lead acid, this would have to be 100%) So you will plenty of charge to heat the batteries.
-- If you are going camping, then you will have to recommission the camper, e.g. turn on the heat, refill the water, etc. I typically start this process the day before. This allows plenty of time for things to stabilize and, typically, shore power is available.
-- If you are not going camping, then again, you will have the batteries around 50% charged and turn off the main battery disconnect. N.B. This is the battery disconnect, not the load disconnect. If you are simply going to run errands with the vehicle, leave the batteries disconnected. If you need to use the camper batteries at this point, e.g. for lights, then you may want to be sure that you wire your vehicle so that you have a charge disconnect switch. This is easy to do. In Coguzzi's case, the Manager 30 should do this for him automatically, assuming that all of his charge sources run through the Manager 30 and none bypass it. (A separate solar controller might be an example here.)
If you need to commission the camper and the batteries are cold, then manually turn on the heaters and give them four hours to warm up (overnight) before applying charge. Joe917's "cold start."
In any case, the BMS should act as a final fail safe.
Does this make sense?