I don't think your proof is sufficient. Only giving merit each other can't proof merit abuse or merit trader. I think you should obtain more info if possible.
If they are alts they will be tagged for sending merits to alts. I can't prove yet, that fakegurutu is an alt, but it's very fishy.
At least hisori and sham100899 are alts because they used same BTC address.
Let's wait how DT decides if fakegurutu is another alt of hisori/sham100899.