According to Osho, a tirthankara can take a physical body again only by deliberately not discarding the ‘fourth body’ at death—keeping a single, powerful last desire: to return and guide others. This retained “peg” preserves the bridge to rebirth. Such return is rare, pre-arranged in mystery schools, sometimes aided by higher beings, and is considered supreme compassion.
Yes—if they keep a tiny, selfless wish to help others alive at death, their inner bridge stays and they can be born again.