You could usehave a Polymorphfriend cast a Polymorph spell to make your displacer beast polymorph into SOMETHING like a giant vultureany beast, and cover most ofthen your ranger can cast the requirementsSpeak with Animals spell.
I aked a question about this. You can view the questionI aked a question about this. Polymorph only works in concentration, so your ranger would not be able to seecast it to get rid of the answer displacer beast's form for up to 1 hour(so don't sleep in inns). But But if you don't want to , the answer we decided was "yes". And sincehave a giant vulture(or chosen equivalent) can't speakvery helpful buddy who doesn't get distracted easily, the polymorph spell would be satisfied. Since polymorph would remove the sighting ofyou can change the displacer beast's body, all would be satisfied, and people would relaxform. Obviously, you could find aThe wand of polymorphSpeak with Animals if you don't want to or can't cast this spell yourself.
But other than that, stick with the homebrewwould Speak with Beastsonly affect you and your displacer beast. You can have multiple castings, too.