Alrighty, I deleted the original post as it kind of confused me. Between the plethora of Mandalorian lore and my screening “hopping” on my as I typed it confuddled me. So, I’m rewriting it in Word and reposting it, hopefully to better clarify things!
First, we’ll look at the True Mandalorians. They were seen Pre-Clone Wars originally under Jaster Mereel. They are not Mandalorian Protectors rather a precursor group. Originally seen, they wore silver or unpainted armor with color accents to denote rank. It would seem that red was the color of the leader or leaders, blue being the next highest rank and yellow being the lowest rank. Later in Jaster’s life and into Jango’s reign, we start to see the green appear on the armor in lieu of the silver, although the silver is still present, especially among the leader cast. The rank colors stayed the same.
Now, onto the Journeyman Protectors and Mandalorian Protectors…
Journeyman Protectors are the "Law" on Concord Dawn. They are essentially like the planets Marshalls. Jango's biological father was a Journeyman Protector. It's unknown if they wore armor as none have been seen in armor, at least that Im aware of. The only identifying mark known to be for the Journeyman Protector's to date is the red girthbelt. If you notice, neither Jaster Mereel nor Jango Fett wore the red girthbelt. Jango did wear a brown bolo belt of similar design but not the same thing. The red girthbelt is the associated piece to Journeyman Protectors. There are canon sources that state Jaster was Concord Dawns JP prior to Jango's father, some of that can be canon ambiguity relating the creation of Jaster and one of Boba's possible backstories. I cant say for certain if Jaster was or wasn't. However, we do know Jango's biological father was and Jango was not. The last corrected backstory for Boba had him serving as a JP for a time early in his life post Clone Wars.
Mandalorian Protectors were supercommando's originally formed during the Clone Wars. They are essentially the standing army of the Mandalorian sector of space and follow the Resol'nare as laid out by Jaster Mereel. The tie in factor here is the armor color, the green base color on all of them. Outside of the old Marvel Comics 80's stories there isnt a whole lot on the Protectors. Mostly alot of speculation, kinda the same as with the Journeyman Protectors. The JP's were isolated to one planet in the sector while the MP's were the entire sectors military.
Now, speculation only, based upon modern era sources, it seems that when the Mandalorians unite under the Mandalore as a united military front, they seem to repaint their armor into the colors of the protectors. There is source material for this from the 80's Marvel Comics which included the Clone Wars Era and the Rise of the Empire Era's. Newer dark Horse comics show it again during the Legacy Era under Mandalore Chernan Ordo and there is a story set during the Vong War where Boba and a group of Protectors, essentially all duplicates of him, battle Han Solo as a test for combat against the Vong. It's unclear from source material if the Mandalorians all wore the Protectors greens during the VongWar or not. But, in the one story from the era where we have a visual reference, they do.
Also, by the time of Vong War, Boba had renamed the MP's to the Ori'ramikad. Most written chronicles by the Legacy of the Force Era have his Ori'ramikd wearing their own look. Although the colors of the MP's are still prominantly seen on Mandalore.
Now, during the height of the Mandalorian Protector’s, our best references are Boba Fett, Spar, Fenn Shysa and Tobi Daala. All were Leader cast and wore the green’s with red trim on the helmet and a variety of green’s blues, reds and yellows on the armor accenting the primary greens. Jodo Kast’s armor is Mandalorian Protector from a series of speculated sources. It was somehow scavenged. It may have belonged to an unknown MO or it could have been an extra set of Boba Fett’s. The primary base color was green with all yellow accents. It’s rather unclear if there was a color coordinated to rank system as we only see leader cast wearing red and Jodo Kast in yellow or unknown rank or origin.
By the Legacy Era, under Chernan Ordo, the Mandalorians are back in their Protector greens. From the artwork, Chernan Ordo, the Mandalore, is wearing a new mask of the Mandalore, the kreb’es, for a helmet. The mask seems to be forged to the helmet like Canderous Ordo’s was. SPECULATION… same surname, possibly related, possibly the same helmet/mask or a modification of it. Perhaps a whole new mask for the Mandalore. Anyway, in addition to the masked helmet that Chernan Ordo wears, he’s wearing blue and yellow accents on his armor. His shoulders are blue his gaunts are yellow. Hondo Karr is seen in his Protector get up as well. He seems to be a lesser leader cast and has yellow and violet accents on his armor. Yellow helmet trim, gaunts and knee’s, violet bicep armor. There are some other’s pictured and not named. Most seem to have some combo of yellow and blue on their armor. Vevec is another named Mandalorian with the green base. All of his accents are violet… helmet trim, gaunts, and biceps armor. Now to further confuddle thing, Yaga Auchs seems to be of a leader cast, lesser than the Mandalore but higher than Karr. He’s wearing armor that is possibly a brown or antiqued gold/bronze/copper in color. His shoulders and gaunts are green. He’s seen killing one of his subordinates wearing the same armor but with yellow helmet trim. Auchs isn’t seen in helmet so there’s really no way to know what , if any color markings their were on his helmet.
From the whole “history” of the MP’s, I wouldn’t be too caught up on color denoting rank. It could mean anything from rank to unit affiliation, clan affiliation, personal preference etc.
The key for the MP’s is the green base color, auxiliary color(s) are personal preferance as well as shade of green. However, it would be most accurate to avoid very bright greens. Greens of the olive, drab, sage, moss etc seem to be the best color matches.
I know that was a lot more than asked but hopefully it helps to clear some things up!