When you are setting up the team with HQM you choose if each member receives the loot or if it is shared. As for getting crazy lootz...crazy lootz are goodI'm not sure if there is a way to do this.. but if it's possible to detect multiple players in a team in HQM then it might be a good idea to use that and reduce the awarding % for higher ranking loot bags with multiple members. Two of us are getting some crazy awesome reward bags.
This is a known bug. I 'think' it's a forge issue that no one can figure out but I'm not sure. I know that some of the diamonds I have do not stack with other diamonds, but I can use them all to make a block.Also there is a lot of items not properly stacking in 2.4.3 (3 dirt and another 4 dirt won't stack even though item ids are the same). I've seen this in the Direwolf 20 1.7.10 pack so FTB team can probably help out if you don't know the solution.
As for the issue you had with the coins, I would just delete the save and start over. You are at the beginning anyway. But that's just me. You might also be able to use an NBT editor to poke around and find the issue, but that seems like a lot of effort for no real gain.