Question: What did Raphael mean with the Josè Canseco joke? I've been wondering for over 20 years.
Answer: Canseco was a star in the 80s, so a bat with his name on it would have been very expensive. Raphael is basically calling him a thief, probably because he doesn't look like he can afford it.
Answer: Jose Canseco had one of the best baseball careers, so anything with his name became priceless but it all came to an end when it was revealed he used steroids.
Question: When Splinter is being held captive by Shredder how was he able to survive? He seems to be held by him for quite some time so shouldn't he have been dead?
Answer: Meditation, by putting themselves in a deep mental state, they could go days without food or sleep. It's said, that some hardcore mystics can actually stop their own hearts.
Question: What was Shredder's plan? Surely he'd have the Foot go beyond petty thievery eventually. I never saw it addressed in the movie.
Answer: It's not really petty thievery. Shredder essentially has control over a large crime syndicate which is involved in pickpocketing, burglary, and highjacking. And that's just the gang itself. The Foot Clan itself is probably involved with other activities that we haven't seen.
Chosen answer: He simply doesn't like Canseco, which is why he sarcastically asks Casey if he actually paid money for the Canseco bat.
Phaneron