Following up in case anybody else is interested.
1) Installed Growl 1.3 from the MAS; from what I can tell, it did NOT come with the traditional Extras (GrowlTunes, HardwareGrowler, GrowlMail, growlnotify). I already had HwG installed, so if it was installed when the MAS version installed, I didn't notice it. I'm assuming that if one wants these extras, one would have to download 1.2.2 and install them from there.
2) HardwareGrowler still crashes on Lion, even under Growl 1.3. In fact, it seems to crash more frequently. At this point, I'm not sure there's a good reason to upgrade to 1.3 besides showing monetary support to the development team, as 1.2.2 itself ran perfectly fine, and it was HwG itself that needed updating.