Moblin Base - Stage 1
Step on one of the large leaves to reach the next section and have each person pick up an equipment. Next have the bomb guy destroy the obstacles on the left pedestal, then throw a bomb guy and bow guy onto the pedestal to the right. Now, fire an arrow at the switch then quickly throw said bow character to the left, and have him shoot that switch as well to drop the bridge down.
Moblin Base - Stage 2
For this stage all you really need to do is defeat all the enemies to proceed. Apart from the three-tier Deku Scrub which requires arrows to kill, the rest can easily be dispatched with bombs.
Moblin Base - Stage 3
Start by having your bomb person go solo and scout the area to clear it of enemies. Once that's done, take everyone to the puzzle section where you must throw a bomb onto the grate to activate the switch below. This will open a big wall and reveal five switches, so have a totem of two guys shoot arrows at the three higher switches and then have the one remaining character take care of the two lower ones. Take note that this needs to be done quickly before the time runs out.. Take the key and throw it back towards the main area to open the gate leading to the end of the stage.
Moblin Base - Stage 4
We're at the boss level once again, and this time you'll be up against a horde of Moblins. There will be targets on the ground, targets on totems and targets on towers. Stack your characters appropriately to deal with these enemies, and of course arrows and bombs are the preferred weapons to fight with. The treasure chest in the area contains some 20 rupees by the way.