Cafe Claude would be tough. It's pretty small and it's not business function efficient.
Wayfare would be the safest (assuming you have the budget). It's a celebrity chef restaurant, has lots of good standards, has cocktails etc. The menu is self-explanatory.
I think Perbacco would be the winner if the group is open to a smaller menu and ingredients they may have to ask about (e.g. chowhound types).
I attended a business lunch at Wayfare Tavern last year, with about 30 people. They put us upstairs at a long banquet table and served salads individually and then the rest of the meal on platters, family style. They have the kind of food that lends itself to this setup. I'd rank it among one of the better business function meals I've had. I have not been to similar functions at the other places you list. Perbacco and Cafe Claude are my favorites on your list in terms of food, but I have no sense of how they would be for your purposes.
I would say Perbacco could be best in terms of food but not sure if they can handle 20 people, and they are probably the most expensive.
Aside from that Wayfare Tavern is probably next best on your list. The upstairs room can handle 20 and they have very good food.
The only one to take off your list for sure is Morton's. Haven't been to Bluestern and I never hear anything good or bad about Scala's Bistro.
The food at Cafe Claude is good but I think Wayfare Tavern would be better for a business dinner.
Doesn't depend -- at least in part -- on budget?
-- Wayfare Tavern is good, not great, but it would be fine for a business function.
-- Scala's would work, too. Again, food good, but IIRC, the chef has changed since I was last there.
-- Bluestern (never been there).
-- Morton's is a chain steakhouse . . . they are, I'm sure, set up to do business dinners, but it's not going to be an only-in-SF function.
-- Love Perbacco, and they have a private dinning room perched over the kitchen.
-- Café Claude can be fun, but a) it's been years since I've been there, and b) I'm not sure about doing a business dinner there.
Just my 2¢. Probably worth far less. Keep the change . . .