Mind you, do you remember the National's production of 'Wind in the Willows'? All the animals were achieved by using make up and costumes. The rats has long brown or pink tails attached to costumes and brown ears on hats. Some were evil gangster type rats, not like Ratty. You could buy some joke protruding teeth for the rats to wear and do brown make up, darker noses etc.
When I copied the make-up ideas, my tails got the right swing by using plumbers foam as the base of the tail and stretchy pink or brown fabric for the tail and some light foam. Down the cantre ran some masking tape covered garden wire so that the tail could be curved and yet pliable. You cover the wire with the foam and the foam with the stretchy fabric stuuffing the root of the tail into the plumbers foam base. The end should taper. Stitch accordingly.
Phoebe