Well, I think the pond is no more. Last week's rain soaked in an helped the dirt settle some more, so I worked this morning on shoveling in more dirt, racking it smooth, tamping it down, and adding more dirt on top of that. It's starting to rain now (and more is predicted for this evening), so we'll see how it continues to settle. There is plenty more dirt available, and once it seems stable, we'll put down some grass seed to hopefully at least cover the area until we know what we're going to do with it.
I also took a few shovelfuls of dirt to fill in a depression in the front yard; I imagine I'll be spending some time loading up the wheelbarrow and wandering through the yard looking for soft spots, dips, divots, and other holes. And there will still be plenty more dirt available.
While Celeste took her morning nap, Evelin helped move bricks and we now no bricks on the patio. I also removed a few more of the timbers, which revealed one problem: While the ties are held together with 1-foot pieces of rebar, the bottom course is secured to the ground with some pipes that are nearly a yard long (or at least the one I was able to get out was that long). They're making that bottom course (and in some places bottom two courses) quick difficult to pull out.
Now the question remains: What to do with all that remaining dirt? One suggestion has been to just leave much of it there and to build a deck over it. That just seems messy to me, but it may turn out to be the best solution, particularly if the deck is at the level of the old patio or even a little lower. We could have the sides solid or latticed (instead of having a deck up on stilts), which would hide the dirt nicely.
So ... I guess our next step is to keep shifting dirt around to be able to pull out timbers and to knock down the level of the dirt, and to figure out if we want to try and build something ourselves or if we call in professionals.