In the manga, Sasuke doesn't regain his Rinnegan. The story progresses without this particular change. The power he had before is maintained without reverting or regaining additional abilities related to the Rinnegan.
Thor's getting his eye back in the comics depends on the specific comic arc. Sometimes it happens as part of a major plot twist or a heroic achievement on his part.
Sure, Gon gets his nen back in the manga. The process is quite complex and involves multiple plot twists and character interactions that contribute to his recovery.