I do not have Traveller 5, but figure that I need to get it so as to know what is in it and what is not, and what could be produced for what is not there.
With respect to a 100 kilometer wide terrain hex, that can cover a lot of different terrain, depending on where you are, even on the Earth. On the California coast, you can go from temperate forest to mountain to semi-arid plains in that amount of area. In Florida, you can go from grassland to swamp to a coastal marine and island environment.
I am not sure how much the BeastMaker rules differ from the ones in Classic Traveller, which I am going to find out, but looking through Supplement 2, Animal Encounters, again, there are some pretty odd combinations in there.
Is it possible to get 30 and 24 metric ton Hunters in Marsh terrain, medium world, dense atmosphere?