I don't think Soulvester and Ribecca are bigots. They're in the wrong for calling Connie by her old name, but I don't think it insinuates they'd be transphobic, just jerks. If the toons weren't raised in society, they wouldn't have been raised with ingrained bigoted beliefs.
I don't think Arthur, a Black man, and Delilah, a woman, who made half their cast queer and/or have disabilities would make Shrimpo any sort of bigot. He hates everyone equally. Besides, they don't need the guy running up to children and calling them slurs.