The Bumbles are reliable once you make sure that you place their hives in the right Biomes. The Thermometer used on the Hive/Bumbliary will give you the necessary Info. From there you just need to make sure the Hive is Outside for Bumbles you found outside and Inside for any you found Underground.
Also pretty sure i took care about all progression exploits within GT6 itself, so no worries about that.