i am wondering also about viability of the plugin which is at 1.32.3 while current syslevel is 1.34.6. I have some hours invested in this thing, currently on rebuild number 3 after getting a new version prompt. The plugin upgrade option bricks Zoneminder. This thing has promise and someone has done considerable work getting it to its current state which is appreciated. Hopefully development will resume sometime soon.
Just to update, a clean installation test of ZM 1.34.9 on Ubuntu 18.04.4 went off without a hitch. Adding cameras and getting ZM up and running took only an evening. That test went so well that I am reluctingly abandoning the FreeNAS plugin and building a dedicated Linux server for Zoneminder. The plugin shows promise. A substantial amount of work has been done to get it to its current state. Kudos to the folks who have taken it this far. I am sure it will eventually be robust and complete. As for me, a dedicated clean installation fills the need for now.
From what I can see at this very early stage, ZM has been substantially improved, up to the point where most bugs have disappeared and it functions properly. Given your hardware resources, why don't you also run ZM in a FreeNAS jail as a side-by-side comparison? It would make an interesting and telling test with little effort, plus, of course, it would provide valuable feedback on the status of the plugin.