Cannus, Tomb and Brawler are all Reboot-only (so far) characters.
They all first appeared in
Showcase '95 #6 as new Academy members that were being transported there by Apparition and Andromeda.
From memory - Brawler had Timber Wolf-type powers (without the claws), Cannus was a dog-boy version of Dawnstar and Tomb had the power to control people's bodily processes/reactions or something (like make people vomit or get a headache or something I think - kind of a cross between Chemical King and Infectious Lass).
All three were characters with potential I thought but Cannus was the only one who ever appeared again. In
Legionniares #43 he was one of the finalists to join the Legion in their big membership drive after the 'Team 20th Century' split but lost out to Magno, Sensor and Umbra.
The great Cosmic Teams site has a little history of the whole team but no pics of those three, sorry -
http://www.cosmicteams.com/legion/docs/LegionAcademy.html