Let's make it simple:
You build you battery pack according to the required voltage. That depends on inverter/devices that you plan on running from this battery.
Most inverters at or above 3kw, will require 48v. So first choose what voltage you want your battery to be. If it's 48v, then all 16 cells will be in series, with one 16S BMS.
If you plan on running 24v, with 16 cells, you have a few options: 1. Build two separate 8S 24v packs, each with its own BMS. Then you can parallel them. 2. Build one 24v 8S2P pack, with just one BMS (total 16 cells, every two cells in parallel and then each pair in series).
Whether you choose 48v or 24v in either configuration, you could always add another active balancer if you wish, I parallel with the BMS's balancing capabilities.
If you go 24v, I personally would choose 2 separate 24v packs in parallel. That means less load on each BMS and gives you redundancy in case you need to do maintenance on one battery or if one BMS fails.