More experimentation.
Well my old dining hall layout needed to be tweaked a bit, setting it up like the image I posted above didn't give enough dancing space for a tavern once I put all the tables and chairs in. I knocked out the two side walls and widened it, which is giving me enough space it seems. My basic idea was sound though, I've got a big enough dining hall to easily be legendary, a mist generator, statues, and nearby food and drink stockpiles. I haven't bothered with a tavern keeper, and it doesn't seem necessary anyway.
The tavern attracts a good number of visitors, mostly humans and dwarves, but some random cougar woman has been hanging around down there for a while too. I let two human performers join my fort as long term residents early on, but that was a waste because I can't assign them as performers to the tavern. Even after they were granted citizenship, I still couldn't assign them, so I'm denying all long term residence to performers since they just take up space. At least they're doing grunt work as citizens. Mercenaries are better though, since I can put them in the army. I have them in a squad called the "Dorf Foreign Legion" under the command of one of my better fighters. Biggest downside is that the humans need bigger sized armor, and they just show up with a weapon and a shield. They're not even wearing goose leather! So I bought human sized armor and clothes from the caravan that just showed up so they'll have gear, and the human citizens will eventually need fresh stuff to wear too.
Temples don't seem to have much to them yet. All I seem to need for them right now is a 5x5 space plus storage room if I want the dwarves to play music in them. It looks like the temple features don't show up until 47.x. Anyway the dwarf civilization I'm playing has 7 different gods, so they each have a small shrine area for worship. One of the gods is concerned with war, victory, and fortresses, so I put his shrine down with the barracks and weapons and armor storage. There's a god of trade, so I'm going to put some statues of him near the trade depot. Then there's the male god of rainbows and pregnancy who has a small number of very enthusiastic female worshippers...
I have a library up and running, and so far I've gotten some visiting scholars who dropped in and wrote some medical texts for us. And a book about beakers. But there was a bastard dorf scholar who stole one of the books I bought from the dwarf caravan! Luckily it was a copy, and I have at least another one, but this is apparently common behavior for visiting scholars, so I may have to restrict library access. My scribes haven't made much effort in actually copying texts, but I think I might have to adjust stuff in the location screen from what I've been reading. There are enough blank quires on hand, so that's not the problem.