You can untwist hands a little to get weapons through the gap then let them rap up again which holds the weapons. Very secure will never come out until you untwist them out.
My own invention.
I prefer using these then regular minis as they have movable joints.
I've also made a gorilla recently...
Years to late but I had the same idea and this is my very cheap but creative solution, cotton string twisted into rope and pva.
The miniatures are one bit of string and the weapons are separate pva stiffened cotton.
YouTube has many tutorials on how to make rope and twist .
I used this knowledge...