What about those other Omniverses? Assuredly, if there are other Universes, then there possibly could be other Omniverses; for example, our Universe is defined as 'All the possible starting conditions and all the possible ending conditions of the physical plane.'
Could there possibly be other things? For example 'all non-possible starting conditions with non-possible endings? Would that be a useless things, as it could not *possibly* exist?
There's no point in considering other universes if there are no laws of physics that allows information to be transferred from ours to the other ones: if there are none, then on some level it ought to be said that those others don't exist materially/outside our imagination (where are they?); if there are some, then those universes are essentially part of our universe (you just obey whatever the laws of physics are that allow you to get to them; it's just a question of technology, but so is transoceanic flight).
As a corollary, it's also fruitless to consider other omniverses.
The first set of infinities deals with all the possible things that could happen in this universe from begninning to end (what if particle A bounced of particle B instead of particle C in the Big Bang?). This is then a point in a higher dimension with other points being made up of other infinities with different sets of possibilities (e.g. a round earth might be possible in one of these other infinities).
Why is this a point in a higher dimension? What does that even mean? Do you want this to be anything but sci-fi? If so, I suggest that you use the word "dimension" to mean what is meant by mathematicians: it's a direction in which you can move that isn't just some combination of other directions in which you can move.
Sorry, but while infinite sets of universes being points in higher-dimensional spaces may be fun for kids to think about, it is not a serious subject of intellectual reflection, because:
(1) it doesn't yield any new intuition or formality about dimensions or universes
(2) it doesn't, really, mean anything at all.
Now there are infinite possible infinties (or "omniverses") contained in a single point in the 10th Dimension. As this single point covers everything that is possible and everything that is impossible you cannot have anything greater... hmmm, what does the 10th Dimension remind me of?
Yeah, we already have a name for the dimension that's a single point: it's the 0th dimension. Adding a new dimension which is a single point is equivalent to adding no new dimensionality at all. I.e.: imagine you're travelling on a two-dimensional surface, such as a dry sea bed: you can move north/south, east/west, or some combination of the two. You can add a new dimension of motion by filling the sea with water: now you can move north/south, east/west, up/down, or some combination of the three.
You can restrict how big the new dimension is by adding a finite amount of water: if the water is 100 meters deep, you can only move up/down 100 meters. At every point on the sea bed, you have added a vertical line of "climbable" water 100 meters long. Suppose you make the water 0 meters deep (an infinitesimally thin layer of water): at every point on the sea bed, you have added a vertical line of "climbable" water 0 meters long, otherwise known as a single point of water. You can't move along this line of water more than 0 meters. In terms of ability to move, you haven't added any freedom at all.
This is the sense in which dimensionality is discussed in earnest by people hoping to get somewhere. Please do not feel that your imagination is being repressed or that your mind is being closed here: higher dimensional spaces are already wondrous, confusing, and enlightenment-prone enough without being reduced to the senseless ramblings of a pseudoscientist and his wannabe bestseller.