I don't really know that specifics, i believe that all triggers gives you the same ammount of def. But seeing that Beowulfs "element" have advantage against Vanguards, it's not impossible that this could be real too. If you find the answer to this, please post here on this topic! I've never really dived into this kind of "advantage". But as damage goes, Beowulf is your best bet damaging Vanguards, killer bee JCs are insanely good against them.
i think every weapon has some sort of dt stat advantage from an unreliable memory it went
rebellion- increased regen(Probably wrong, not noticing it much)
beowulf-increased def( from fighting jester this would seem true enough, no proper checks done)
agni and rudra- elemental damage tables value increased, so enemies are weaker when they ar weaker and stronger when they are strong,or something (not known wether true)
nevan- no idea, maybe air raid? though that seems more like a skill then a buff
cerberus- definite speed boost
ok now i've definetly gotta try it again