Continued...
When I got home later this evening, the clowns were acting fine. I watched them for a good 20 minutes and didn't notice any flashing, darting, etc. The smaller of the two did spend a little time under the flow, but not the whole time.
It may be that I'm just paranoid because I am SO close to getting them healthy and in my display. I lost a pair of clowns a few months back, to brook, I believe

(One of them hung out under the flow a lot, so that's why that behavior catches my attention.)
Also, I notice the female is not picking on the male as much, so maybe the strange behavior is just more weirdness of the clown bonding process. As I type, the female is in the flower pot, and the male is hanging around beside it. So they still haven't fully bonded yet.
One thing that I'll have to check closer in the morning... it kind of looked like the smaller fish had a light dusting on him, which really scared me. But I could only see it when I shined an LED flashlight over them, and of course, that didn't last long because they immediately hid. I won't be convinced of this until I get a better look.
Hopefully they will be free of white poop and other strange symptoms by tomorrow!