There are 9 gremlins in the crimson order.
According to the wiki, there are only 9 notable gremlins.
Seerus
Herex
Gracken
Groat
Punch
Vise
Nonna
Razwog
Sputterspark
If you're an active, longtime player, you should know that:
Seerus - Defeated
Herex - ???
Gracken - A gremlin in Emberlight
Groat - Possessed by Dread Velvet in Caketastrophe Prestige Mission, then exorcised, found to be a nice gremlin
Punch - The Variant smith in Haven
Vise - The Unbinding smith in Haven, also known for being in the mission lobby of the Seerus missions
Nonna - The emberlight adoption agent in Haven
Razwog - Defeated
Sputterspark - Defeated
So here are my theories. We only have 9 notable gremlins so far. And there are supposed to be 9 gremlins in the crimson order. So...
Herex has a secret affiliation with the Crimson Order and will be joining back soon, or will join US to defeat the King. I also think he might be the final boss in spiral knights, as he has a connection with the Swarm. (see Spark and Roar)
Gracken is a spy in Emberlight and plans to feed info to the king so that the Crimson Order can destroy Emberlight.
Groat is a secret member of the Crimson Order and fakes his innocence.
Punch is a spy in haven and will be soon replaced by a spiral knight.
Vise is a spy in haven and will be soon replaced by a spiral knight.
Nonna is a spy in haven and will be soon replaced by a spiral knight.
I think that the 9 notable gremlins are part of the crimson order, while 1 of them is a traitor, or a true member.
We have 3 spies in haven that will soon leave, and will be with the Crimson Order when they raid Haven.
Emberlight will be destroyed by the Crimson Order because of Gracken.
Herex is unknown, and a mystery to us all.
Thats my theory.
I think that 9 gremlin bosses is a bit impractical and absurd. What needs to happen is for OOOs to pull a "clever" plot twist and have one of them turn on the crimson order, two or three of them die to Herex, have one of them get eaten by a tortodrone... whatever it takes to prevent 3/4 of the bosses from being gremlins. We only need to fight like 3-4 of them for this to work, and the 3rd and 4th one can be added in later on. If we need more high tier gremlin foes, I'm sure they can be written into the story or even made to operate outside of the crimson horderve.
OOO probably knows this, and has put a good deal of thought into it-- so for traitors etc. to exist, yeah, I think you're right.