Your ability to present the current state of scientific thought in a calm and sensible manner to an, apparently, hostile human is remarkable. Keep up the good work.
I think the baloon example is great! I wish there was a good four-dimensional example but only the universe itself seems to give that. Space is expanding away from the earth in all directions. This does not imply that the earth is the center of the universe; in fact, all space is expanding away from all space if I understand the current state of scientific thought.
I am also impressed with the inflation theory. I think pro-matter and anti-matter (true nothing) is a great concept.
The two of you mentioned that there is not much in space except some light (and clumps of matter obviously). I think the underlying structure of space is gravity and that gravity permeates everything. At least one very early scientist thought there was an ether and I think gravity will prove to be it.
Best wishes,
Bob, Alice, and Eve