I've come to the conclusion that I don't have an absolute favourite Disney character, but there are many I love! I tend to favour the characters that have hidden depths to them (e.g. characters where there's more to them than you expect); I am especially fond of this trait in villains. I also generally have a soft spot for animal characters, particularly the ones from Disney Princess movies!
I don't have an absolute least favourite either. But the characters I often dislike (rather than hate) in Disney movies are those that lack personality, more than anything. Even if a character has a good backstory, I tend to get bored if their personality is not very interesting. I dislike stereotypes too (and sometimes hate them), although I admit I will
sometimes be able to forgive a stereotypical character design if the character is entertaining in some way!
I can at least give you an idea of some of the characters I love the most with the picks I've created in this spot so far:
link
I haven't done anything based on my least favourite characters, but this will at least help you see which types of characters I tend to favour. :)