There’s a lot in your post and I won’t address all the issues. But I’m sorry for bad experiences in the past.
When you use Sitelok and Disqus SSO plugin together there’s nothing for your members to do. They don’t need to create a Disqus account: Sitelok has done that already. And their comments are private to your community. Disqus does provide some options: ordering comments from oldest to newest, or visa versa, for example. But these are basic. Perhaps the only thing you’d want to inform members about is they can receive email notifications of additional comments if they want (there’s a little subscribe button that is visible and optional with a Disqus button).
Now let’s go beyond the blog a bit. This part may be irrelevant to you, but at least it’s worth knowing about. With Armadillo you can create solo content areas. The big thing is these are not blog posts. This content could be on any page, or make up a complete page. You can also add a Disqus commenting to that page and due to the Sitelok + Disqus SSO plugin members can automatically comment on that page if you want. (This is great for group activities, or basic planning where you want feedback, or for many other uses.)
As long as your focus is on “members” and not the general public, then you’ve made a case for Sitelok. It’s as simple as that. This means, presumably, your blog would also be for members only.
… but since all of this is new for you I would suggest building up bit by bit instead of everything at once. For example, create the Armadillo blog but with Disqus commenting turned off. Once you have that down well then add Sitelok. Then add your members. Once you have that down well then add the Disqus SSO plugin that works with Sitelok (I think this costs an additional $15). Once you have that done you can activate Disqus commenting on your blog page and anywhere else you want.
… or if you’re really worried about others looking at your work before done then do the opposite. Install Sitelok first, Apply to all pages (or all “relevant” pages). Make sure the only member who can see the page is you. Simple eh? Now when you publish there’s only one person who can see the content on the web. Later add Armadillo and other stuff.