Caveats:

I am NOT a powergamer, and therefore am interested solely as it affects play in SoA, not ToB. Tactically I prefer to play an artillery+finesse game, and therefore stay light on tanks. Please keep this context in mind when making replies.

Currently:

Protagonist: "Fish," Ftr., Reformed Assassin and Pickpocket, TN. Primary proficiencies in longsword, 2h-sword, and crossbow, w/ occasional outliers for amusement value. (Modeled loosely on "Old Man Fish," from Glen Cook's "The Silver Spike.")
Viconia
Edwin
Jan
Yoshimo
That Dwarf

I intend to restore Imoen into the party, as she amuses me.
Therefore, when I get rid of That Dwarf, as I surely shall (personal bias, he simply irritates me), I have a choice before me... amuse myself with Nalia, or with Cernd? In this party, which of the two provides the greatest amusement value?

Or, entertaining a tactical question, if one were picking up all the wacky ones and opted for Cernd, under what circumstances would Nalia or Haer'Daelis be sufficiently interesting to justify replacing Edwin, who is long on spell-slots and short on divination and shortbows?

Yes, I know I'm mage-heavy... very much so. I just enjoy all the finesse options that such a party provides... and the lovely chaos that ensues when something gets screwed up and chaos ensues, with the protagonist bleeding profusely and Edwin parrying desperately with a stick, while Jan gnaws on somebody's ankle...

Minsc is fairly amusing.

Nalia is laughable in the more pathetic sense, not really funny.

*all we are saying is give Cernd a chance*

Nalia vs. Cernd?

Well Nalia has more banter but Cernd has another sidequest while Nalia's quest should be long over by now.
Cernd almost never gets picked but can be nice too, Nalia can be extremely annoying.
HaerDaelis is of course the best choice of all. He's a good fighter and a nice mage and he's going to be great in ToB. Also he is by far the most wittiest of them.

Well when would Nalia be interesting enough to replace Edwin?
Maybe when she has a duck sitting on her head?

You're right, Minsc is flipping hilarious... but I'm doing the alternates now...

So, using Nalia for her quests seems okay... how to balance then, between Cernd and Haer'Daelis? They're such different characters that I find it hard to fathom making a useful "amusement value" comparison... (I've never been able to tell whether Haer amuses me, or strikes me as an ass, or, like Edwin/Anomen, amuses me because he's such an ass.)