So the relevant ruling is
The brownie, faerie dragon, imp, lyrakien azata, mephit, quasit, sprite familiars, granted by the Improved Familiar feat, use the Biped (hands) section of the chart. The carbuncle and voidworm protean, familiars granted by the Improved Familiar feat, uses the Serpentine section of the chart. If you do not own a copy of the Animal Archive, your animal companion may only use barding and neck-slot items.
The Cassian appears to be PFS legal (on page 251 UM) but it was not listed in the ruling. I am thinking that it does have hands, since it could always turn into a small human angel, but i can not find a ruling on this. Has anyone else ever seen an answer to this?
