The nicely and carefully written questionHave any animals that have been studied onboard the ISS come back alive? has an affirmative answer that applies to the space shuttle. Now that return to Earth comes in capsule form, have animals ever returned live to the surface - by design?
A nice example would be the recent splashdown of the first SpaceX Dragon capsule to have been re-used after a previous visit to the ISS.
See for example Spaceflight Now's July 3, 2017 article Dragon capsule returns home with animals and station equipment:
Items stowed for Dragon’s return included live mice from an experiment to investigate the effectiveness of a therapeutic drug to promote bone growth, combating atrophy in astronauts in space and osteoporosis patients on Earth. The mice will be euthanized and examined after landing.
below: "The Dragon spacecraft was lifted onto a boat for a trip back to port in Southern California following Monday’s predawn splashdown. Credit: SpaceX" From here.