"Guido" can be a derogatory term for Italian-Americans, but it's also a well-documented Italian/German name. It's been a name since the 11th century, long before any negative connotation arose and it's still used as a name to this day. I mean, wouldn't it be kinda worse if Guido both had his name and acted out an Italian character type? That could be seen as an actual stereotype, but as it is, it's just the play on a well-established human name. That's all the purpose it needs.
In any case, I don't see the problem. It's an actual name, children aren't likely to notice nor care, and it's not like no other characters have ever been named Guido. Pixar's Cars, Marvel comics, frickin' Samurai Pizza Cats, all of these use the same name for a character. I wouldn't read too much into it.
