twells: PFS has it's own house-rules. As such, it doesn't have to follow the actual rules. The developers should have voiced objections before they printed rules that clearly allow animals to qualify. Developer post disapproval doesn't overcome actual printed rules.
As far as "So which familiars have can clearly use wands and how do I back up the reasoning if asked?". I think the familiars CLEARLY stated as being able to use a wand, scroll, or staff is the best way to "back up the reasoning".
"As long as the familiar can speak (like most improved familiars and a few birds) and hold or wear the item as necessary" is the current standard. Note, BIRDS are listed so I don't see how that's 'hair splitting'. It'd be 'hair splitting' IMO for someone to exclude said raven, not for inclusion. Also, a bird doesn't need to move it's beak to vocalize so it can clutch that wand in it's beak.
For other non-improved familiars/birds, the check is #1 speaking and #2 hold or wear the item. A Ring of Eloquence easily covers the speaking part and holding works for many as fine motor skills isn't needed just "hold".
Avians and Biped can wear rings so Monkey, Dinosaur (compsognathus), Bat, dodo, hawk, osprey, owl, parrot, raven, rhamphorhynchus, snail kite, thrush, toucan make the easiest item users. Others need non-slotted rings or the extra item slot feat plus a holding method.
If you have to explain the particulars of each animal's physiology and use other other items do work around the core rules, then I would argue it is not "clear".
You obviously believe otherwise - I get it. It's the OP GM's call.