Long as the Neon continues to school with the others it's no really severe problem. Schooling fish segregate themselves (or get segregated) instinctively in life/death situations.
With constipation,quarantine isn't necessary with Epsom salt used in general treatment. It's safe for other occupants and filtration. Epsom salts bathes are a temporary treatment that requires only a small vessel for a very limited "dipping",so no separate tank is needed there either. Bathes may not be needed,so don't see the point of added stress in chasing and netting.
Unless you have really temperature sensitive fish (some of the more southern or mountain Corys for example) as tank mates,IMO a gradual increase to 80-82F for a bit might help.
Just think about it.