Koishi has a new winpose referencing Terry Bogard.
Futo is a hen - she's cowardly.
Marisa is a magpie or crow, a thief-collector.
Ichirin and Unzan are more than a monkey king reference. They are a bunch of classic manga references. I think.
Reimu is a white fox, a noble messenger of gods.
Hijiri's treadmill is her rosary. The reference is probably the same as Nazrin: a silver mouse sent by Bishamoten to save a besieged city. But we are not even sure this is the idea behind Nazrin.
Kokoro is a tengu mask.
Futo's new spell card resembles GGXX Zappa's curse and Sanae's divination, causing random things to fall from heaven depending on the result of divination, including a gigantic UFO.