Are dancing lads in Nautanki effeminate themselves and live compelete makeover and lifestyles as girl forever?

No, they don't have to. They move on and have normal lives later on. Dancing doesn't mean they will continue to effeminate for the rest of their lives. Dancing is an art, not limited to women alone. There can be exceptions though. In any case, the trend of dancing lads is on the decline with the decline of nautanki.