That makes for a very tough go at removing the tank but there is also a reason for hope due to the way things work. Reasons for leaks are many but freezing is the one which gets the tank, while freezing and lots of smaller things can get the tubing and fittings that feed the tank, so it pays to assume other leaks before the tank is removed.
fittings are a good place for water to collect and freeze but if freezing is not the real cause, things like loose clamps or tubing which get cut, rubbed or out of place are more common than actual tank failure.
I would start at looking at all the tubing and fittings that I could see first, trying to trace any water back to the source and that may require removing some of the insulation/covering on the bottom but much less than removing the tank.
If you get into any cutting, do it very carefully after checking for wires, plumbing around the cut.