These are chat archives for BSData/wh40k
in exactly the same way Rubric Marines in the Index have been replaced by the ones in the CSM dex
Not exactly. Codex does not trump/replace another Codex unless explicitly stated (as in, has the same name or is in another way obviously replacing like Daemonhunters->Grey Knights).
Q: Can successor Chapters use the Warlord Traits of their founding Chapter?