A DALY BMS (and most cheaper BMSs) don't need to bet set - they will automatically cut-off if you try to overcharge and cut-off when you hit low voltage. Simple - nothing for you to do. You will need a charger to charge this thing up.
>my plan is to route the output to a BlueSea fuse panel
A simple fuse between the battery and the 'load' is certainly a good idea. Some might do a circuit breaker so you can actually turn the battery on/off as well.
>understand how effectively this simple setup can function.
A 4s LifePO4 voltage range is pretty flat so it will act as well as a lead-acid alternative. If the fan works on the regular lead-acid, it will likely work OK with 4s LifePO4 as well.
You can explicitly regulate the 12vdc from the battery using one of these -
https://www.amazon.com/Voltage-Stab...dldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN
You do need to figure out the max amps you intent to pull from the the battery... for fuse sizing (above) and perhaps for some loads that are regulated.