I'm fne with helping to appraise and gaining advantage so long as there's a reasonable basis for the character knowing a little something-something about an item in that character's background. For example, Guran and Fulgrim are both dwarves, so either of them could help appraise the glaive. Or Colden, being a fighter-type and familiar with martial weapons, could help appraise the glaive.
Sometimes, however, the group might come across an item that no two of them know very much, if anything, about. If that was to happen, then advantage wouldn't be possible.
Most of the time, though, you guys will very likely get the benefit of advantage on the majority of Intelligence checks made to appraise items. Y'all are smart players and can likely point to to damn near any item and find a "reasonable" tie-in to someone's background.