When I replaced the makers on my 1656 I first used JB Weld. JB Weld will hold them on but still won't absorb a glancing blow like if you brushed against them while picking it up. They are now held on with Miller Stephenson epoxy (sorry NLA) that is even stronger than JB Weld. I still wouldn't call it kid proof though.
The strongest repair would involve drilling holes in the markers and body for music wire for support. Then using your JB Weld.
Pete