Chineseys cannot be hybrids of any other species, hybridization only occurs between Campbells and Winter whites
All hamsters are going to be a bit different. I've seen chineseys with tails so long, they actually could rival that of a mouse! I've also seen chineseys with near to no tail. There's going to be diversity in every species of animal, that's how they evolve and mutations occur. Your hams are perfectly normal