Bob, Banichi, and Mendoza would all be interested in the Luggage ... Bob because it's magic, Banichi as a weapon, and Mendoza because the sapient pearwood would appeal to her obsession with botany, not to mention how many samples she'd be able to pack into it (however I suspect Banichi would soon lose interest in the Luggage because it lacks finesse)
Banichi's innate mathematical abilities would interest Bob, once he was reassured that Banichi wasn't an otherdimensional menace to humanity (aside from his sense of humour, that is), probably especially wondering if atevi can program in their heads without letting tentacled horrors in? Bob's use of a Hand of Glory for both invisibility and as an offensive weapon would certainly catch Banichi's attention, plus any other interesting weapons/defenses he happens to be employing at the time.
Banichi's encyclopedic knowledge of botanical poisons (and, presumably, antidotes) and his love of alkaloids as a tasty part of every meal would have Mendoza scrambling to take notes (I don't think he's ever encountered chocolate ... now THAT would be interesting). Plus they share exceptional physical, fighting, and endurance abilities, wilderness survival and living off the land, etc. ... they'd be trading info on all of that.
Mendoza and Bob would have computers and technology and data accumulation/modes of research in common, plus his knowledge of plants as used in the magic espionage business (mandrake, etc.). And if anyone could come up with the ideal botanical repellent for Bob's fight against hungry things from other dimensions, it'd be Mendoza.
And the Luggage would, of course, hate everybody, though I think it would learn fear of and respect for Banichi very very fast (even faster than it did for Cohen the Barbarian)
I'm sure there's more ... looks as if I'll have to put the early Company books on my re-read list to refresh myself on details.