I take pride in the fact I have eliminated every quest related icon from my Heavnsward map. There's a level 59 quest chain that begins in The Pillars that will answer all of your questions.

Once the Forrest Moogles and the Mist Moogles convene, you learn that the first Chieftain was Moggle. Kupli Kuki then figures out that Moggle must have been changed to Moggle Mog as stories were passed down through the generations. Moggle was also Moglin's ancestor. It is also determined that the current Pomguard is likely descended from Mogguard of legend. The Mist Moogles also have a legend of a group of moogles who went down the world below, seeking to look for a safe place for all mooglekind to hide from the wars between man and dragon. They unfortunately did not return, but are remembered as brave pioneers the world below. It is also determined Mist Moogles have Mog based names in honor of Moggle (though no one knows for sture) while Shroud Moogles have Kupo based names because they're easier to say. Lastly, the Moggles who went down below brought Kupo nuts with them which is why both groups are kupo for kuponuts.