Cut the rebar pieces and mortared in the loose block wall on the south side. It will now hold up to actual building stresses. I'll need to fill in some in the house corner, but that will be a slightly different concrete mixture, and I can do the same thing on both sides to make it look like a design feature. It can actually serve as a short support column as well as tying in some architectural elements. It's all fancy & shit.
And I'm gonna try an experiment. I've chosen my method for creating the windowsills; it's architecturally sound yet provides for some interesting detail. I'm keeping it simple. Really. And it could end up sucking really hard.