For a few of them, I'd like to see special effects.
Wishing for the Raider Lord shouldn't bring him to you... but it should draw him back into the Drakalor Chain, should he have left (rather than being killed).
A wish for the Cute puppy should work if the time limit hasn't been passed and the PC hasn't yet visited PC:6 - in which case, the puppy should not appear in PC:6.
If the Dwarven Mystic has already disappeared, wishing for the Dwarven Mystic should make him/her appear, but only momentarily (with a message).
A wish for an inn keeper (including a dwarven inn keeper) should work like wishing for booze. Wishing for a Cloaked Ratling should result in the PC getting some keys.
Wishes for the Minotaur Emperor, Greater Black Unicorn, and Quickling Bard should all result in appropriate monsters being summoned - minotaurs, unicorns, and quicklings, respectively.
The rest should just produce messages, for which I'd suggest the following (assuming each NPC is alive)...
Old Barbarian - You hear a gravelly voice, "My bones just aren't up to any more adventuring. Why don't you come and visit me in my glade, instead?"
Dwarven Weaponmaster - A gruff voice responds "Gotta keep an eye on my dojo, <laddie/lassie>, and I can't train you by distance."
Grizzled Gladiator - From amongst the sounds of merriment, you hear a drawling voice say "I'm afraid my old Arena injuries prevent me from coming, but I'd love to share a drink with you if you're in town."
Dwarven Smith - You hear "Too busy, lots of work to do" as the clanking of metal and the hiss of steam momentarily fills the air.
Demented Ratling, totally unfed - A pair of eyes seem to glare at you through the aether.
Demented Ratling, partially or totally fed - The universe seems to strain, but it seems unwilling or unable to move such a being.