Currently, only Type 1 communities are being created and these are open access. There's Type 2 - Journal (guests can comment only) and Type 3 - Council (only members can write). There is an issue open on GitHub concerning these, to review the validation techniques. These community types will start with the number 2 or 3, when their creation is supported.

Why are these being described as "different Types of Community" and not just different variants of Role assignment at set up? Because from the perspective of the systems that are already in place, that is the only difference. The only difference from functionality that currently is available within the architecture seems to be who can write a reply Comment and it would seem to be much easier to add that as an option than to try and shoehorn things.

In fact, the best way to design this from a UI perspective is probably to build a matrix/table and let people choose from it.

For example:

With each of those columns having a selection button at the bottom and the Custom column having a pulldown that would allow you to set any default to start with. The Reply column of Council should be a pulldown with those two options, because it's certainly possible that you might want a Community where only a few people have access to posting root content but people manually vetted by Moderators could have access to comment.

There would also need to be a fair amount of explanatory text attached to various things, probably via a nice mouseover, but we will leave such discussions to somebody else who is going to be working on that kind of thing.