1. The all-consuming part was true and not metaphorical as it consumed planets, solar systems and possibly beyond.
2. You might be right on this one, but I think Snyder deliberately left an opening saying that the void has an end for other writers to use, which is what Joshua Williamson did in his later stories, which are direct continuation and addition to Snyder's work, with the Light and the Great Darkness. Also, the Hands operate in the Overvoid to create multiverses, so it makes sense that they exist at the end of this one.
3. Yes.
4. Yeah, I used the wrong choice of word for that one. Perpetua took pieces of the Overvoid to create her sons.
5. It takes place in the Overvoid. Beings like Perpetua create multiverses making up the Greater Omniverse which houses infinite multiverses. So your interpretation seems good to me.
6. Yes, some people tend to see it as a hierarchy, but it's not. I was one of those but it's more Monitor-Mind, Source, Presence embodying the same white void beyond the Source Wall. That's how I see it.
Snyder's approach to the Void is thus vast, impossible but finite and all-consuming, except for beings of the Greater Omniverse and certain gods who can travel through the Overvoid. It's likely also outside all space and time since it's beyond the infinite multiverses, being where they were created in the first place. 1-C should be fine.