Jail management/creation

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Hello good folks of this community!

I've been using FreeNAS since early 10 releases, and I've appreciated the general rock-solidness of the system as a whole.
I've been using a few jails and the occasional bhyve VM and those have mostly worked really well, but there's one aspect I've not fully grasped, even after reading such excellent threads such as this and this, and that is jails and their long-term use and management.

I have setup a few jails that I now have trouble updating to later releases, either because iocage wont let me, or because I've run into errors inside the jail later on (like the version mis-match thing).
I'm not aware if this is at all possible, but I would like a system like this:

1. I create a ”base” jail of sorts. In this jail I make some ”minor” changes, such as setting zsh as the default shell, installing a few packages that I know several other jails depend on.
2. I create several other jails, now based off of the ”base jail” so that some of the dependencies are already filled. In turn, I complement these jails with a few individual packages that make up that specific jail or service I want.
3. When, in the future, I need or want to update the jails the services, I can update the base jail to a release I want, or enter it and update the ”base packages”. This in turn updates all the ”leaf” jails that use the base system off of the ”base jail”.
4. When I want to make modifications to the ”leaf” jails, I simply enter them or issue iocage commands to them to change the ”unique” packages or settings for these jails.

I was hoping that the RELEASES already was a solution of sorts for my problem, but I'm either not understanding them well enough, or there's something wrong on my end (probably the former). Is what I want possible? Is there other resources I've missed that could help me achieve my goal?

I'm sorry for the lack of proper phrasing or terminology (most likely the result of my lacking expertise in the subject).
A massive thanks to both developers and contributors related to TrueNAS and it's community.