Hi Virginia,
I've often seen Captain Hook and Mr. Smee posing for pictures and signing autographs in Adventureland at the Magic Kingdom, usually near the Pirates of the Caribbean gift shop. But I'm not certain they are still there regularly. I suggest you check with Guest Services when you arrive at the Magic Kingdom to see if they can give you any insight into that day's character schedule.
To guarantee a chance to meet Hook, you might want to check out the
Pirates and Pals Fireworks Voyage. Both Hook and Mr. Smee mingle with guests before they set sail.
Unfortunately, I don't believe Perry makes appearances, though his pals
Phineas and Ferb have their own greeting area at Disney's Hollywood Studios. If your son is a fan, he might also enjoy
Phineas and Ferb: Agent P's World Showcase Adventure, an interactive game through the country pavilions at Epcot.
Please feel free to come back to the Moms Panel with any other questions as you plan your visit. Enjoy your time with your family!
Wilma