I am almost certain the "John M" went to West Africa, Nigeria I think and its possible that the others also went there but not sure. I beleive they had 10yr time charters to Esso when they were new, possibly that why they were ordered in the first place.
NICHOLAS M was apparently last heard of by the registers in 1997, under the same name. No other details or confirmation of continued existence known.
FRANK M appears to be still in service under the name GOD PREMIUM and ownership of a Dubai-based company.
JOHN M is Nigerian owned with the name unchanged.