Also hopefully as they got older they would notice and start asking questions about the racist shit in those older cartoons...

It was the 90s; we were surrounded by subtle racism and other forms of xenophobia. I don't really think a little can be avoided in popular entertainment, honestly. You can do your best to write your script and point it out to the audiences, but there's a good chance someone's going to slip-up and include a racist, sexist, ableist, or xenophobic stereotype. The key, in y opinion, is to have enough counterexamples so that the unintentional stereotype is dismissed and not believed.

For example, if you plan to have a sociopathic murderer in your story, make sure to include a sociopathic detective and commentary that lets the reader/viewer know that sociopathy does not lead to or correlate with a person becoming a murderer. Some people will still take away the wrong lessons, but you tried.