Here’s the three part doll arc.
As mentioned in Task 3, Yaiba introduces himself with his name’s meaning.
Toad Spirit is made from a vacuum and a coin purse. Coin purses are associated with frogs and/or toads because when they open up, they look like a frog/toad’s mouth. There’s also the Toad /Jiraiya / Ninja connection.
Task 10 has karaoke instead of regular lyrics.
Nami Uemono seems like he’s based on Marco Polo.
Leon Giordana is clearly an analog for Leonardo da Vinci. His schematics are based on da Vinci’s Codex Atlanticus.
Yaiba: Muteki Shogun from Kakuranger
Toad Spirit: Victrailer from Carranger
Serpent Reptvile Zard: GigaRhinos from Gingaman.
Serpent Reptvile Girado: GingaPhoenix, also from Gingaman.
Task 09: The Paper Crane Ninja: April 16, 2006
Task 10: The Disappearance of Bouken Red: April 23, 2006
Task 11: The Showdown on the Lonely Island: April 30, 2006