What plugins are you having problems with? What python version is your octoprint instance running? maybe your plugin problems are related to that, i have played around installing a lot of plugins on OctoPrint instances on TrueNAS without any issues.
Yes it is possible, i don't have a guide for it, but you would need to try and install mjpg-streamer or another software like that. Check the instructions regarding mjpg-streamer at: Setting up OctoPrint on a Raspberry Pi running Raspberry Pi OS (Debian)
Thank you so much for the guide! All the steps worked flawlessly and I have full access to my printer via the Truenas Core jail.
I do have a question if someone can help - how exactly do we pass the webcam to Octoprint? I've been trying to figure out the URL portion...
hello! thank you for the suggestion 
I am trying to set this up but I dont see my camera as a device within the Ubuntu VM. (I'm a complete noob at this btw). How did you get your cameras to show up?
You’ve got to pass the usb through to the VM within TrueNas. Once you do this, just use LSUSB (in lowercase) within Ubuntu VM and you’ll see the webcams.
How can I find how to pass the USBs on my TrueNas Mobo? I only see passthrough options for the NIC, Disk ROM, PCI and a hard disk. Any help would be appreciated I've been trying to do it this way or trying to use webcamsd within a jail.
Watch this.
Thank you @Victor76!!! I managed to combine this video guide with some input from these resources below. I basically have the webcam enabled inside the VM that autostarts when the VM starts up. I avoided using AgentDVR by using MJPG Streamer.
Hi, thanks for the guide! I have been having problems trying to install Octolapse, somehow it is the only plugin that refuses to install. Have you managed to install it?