The reason you are getting conflicting reports is because cold tolerance is such a subjective area. I won't get into a swimming pool unless it's at least 86, anything less than that is too cold for me, but then the kids are in as soon as it hits 74. The same differences occur in diving. No one can tell you if you will need a wetsuit because no one else but you knows when you feel cold. Glance back in your diving log at previous dives and what you wore for what temps then compare that to the average water temps for the time of year you are going.
And if you really can't make up your mind, bring the suit and take it off or put it on as need be. Better to have it and not need it than need it and not have it.
Whatever you decide, enjoy yourself, you are in for an incredible trip.