My main question is if there is any kind of latency compensation across the four FX chains, to keep them all the same, or if it is all dynamic, depending on what algos are loaded where, etc.
The latency is dynamic for each FX Chain depending the algorithm routing. A simple way to keep the latency of the FX Chains fixed is by building your FX Chains from the bottom up. Once an algorithm is placed in the bottom slot, that will configure the FX Chain to use highest amount of latency (around 3.3 ms).