Well, it turns out that I wasn't quite as done as I'd thought. That hanging bias pin was bothering me, so I took a look at what would be needed on it. I didn't really find anything specific for this circumstance, so I took a cue from the data sheet and added a 100K resistor and 100pf capacitor there, connecting the series to Ground. I think only experience and/or experimentation will tell for sure whether that's the right approach, and whether those are the correct values.
I do hope I don't have to add anything else. Board space has become premium. I'd have to seriously juggle some things around for that. (EDIT: I probably will need to do that anyway, so what's just been done will probably not be the final version of things.)