Long story short, I'm persistently unable to rehire Serana as a follower if I dismiss her. I read about this bug on the Elder Scrolls wiki so I'm not surprised to encounter it, but it never goes away. No matter how many times I reload a prior save, I can't dismiss and then rehire her. Makes getting a steward for Lakeview pretty much impossible.

Do I have to wait for her to get to Fort Dawnguard and rehire her there, or am I just plain unable to rehire her if I dismiss her once? For what it's worth, I chose the wrong dialogue options way back and she won't consider curing her vampirism, but I don't know if that had any effect on this.