Your accidental experiment of leaving the minnow trap in over the winter and it turning into a refuge for the small PK shrimp and crays gives me some ideas of purposeful created habitat for them.
A person could use 12-18" long sections of 6" plastic sewer septic drain field pipe (the kind with holes in it for water flow) and cover the ends with 3/4" or 1" hardware wire or plastic screen. Toss a few small rocks inside for additional surface area within and to make sure it stayed in place on the bottom. Then put these refuge habitats in a foot or two of water near other structure.
A rope could be attached if a person wanted to be able to monitor to see if they were being used.
You may have come up with a new structure idea!
