It’s probably more a reference to Mother Brain since Dark Samus had the red skin in the spirit battle with MB.
Personally I don't see why it can't be a reference to both, some characters do have costumes that reference two or more things.
Though I do say it's more of a reference to Trace seeming as Dark Samus does have a sort of pattern of her alts being references to at least two other Hunters: Grandrayda and Kanden, so it kinda makes sense for it to also be a reference to Trace...
Though I think it is fair to point out Wikitroid says this about D.S.'s alts:
- Blue - Her default appearance, taken from Metroid Prime 3: Corruption with embellishments.
- Green - Changes her visor and shoulder and chest lights to yellow, and her suit to green with blue green accents.
- Purple - Changes her visor and lights to a bright purple, and her suit to a deep purple. The color resembles Gandrayda from Metroid Prime 3: Corruption and is used to represent her during her respective Spirit Battle.
- Dark Red - Changes her visor and lights to yellow, and her suit to dark red. It resembles Samus's sprite in Metroid II: Return of Samus, when colorized through the Game Boy Color.
- Gold - Changes her visor and lights to light blue, and her suit to gold. It resembles the Golden Torizofrom Super Metroid.
- Silver - Changes her visor and lights to red, and her suit to silver. Resembles concept art of her from Metroid Prime 2: Echoes.
- Black - Changes her visor and lights to yellow-orange, and her suit to black. It may be inspired by concept art of her from Metroid Prime 2: Echoes.
- Pink - Changes her visor and lights to purple, and her suit to a dull pink.
So... it could be either way tbh, then again I really only go by the references in Aarontimar and his costume origin series since he usually digs really deep into those.
Either way, might mean Sylux would get some different alts than we think or not, who knows. Though if he gets a new design in Prime 4 and they do an Ike sort of thing it could alternate between:
New design
Old design
New design
Then so forth, of course the first two being default colors and the rest being the alts, and assuming Dark Samus has three hunters I think the rest would go in this order for references based on this pattern (including the defaults for it to feel complete)
Sylux (New/Potentially New design)
Sylux (Old/Current design)
Rundas (Because the potential new design would be console title and not a portable title, makes sense to be a color swap of the console game design of Sylux's potential new console game look)
Weavel (Debuted in Hunters with Sylux in a portable title, makes sense to be an color swap of his old/current design)
Ghor (Same reasoning for Rundas)
Noxus (Same reasoning for Weavel)
Federation Trooper/Federation Force (Federation Force is the game that propelled Sylux into his chance for potential future appearances, it'd make sense for a color swap of the game that kicked off this new story revolving around him would be on his new design... which we could've seen a slight glimpse at in that secret cutscene, correct me if I'm wrong on this if someone ever took the time to datamine FF and found the model for that scene... which I highly doubt happened)
Spire(Same reasoning for Weavel).