Well, we did the math: 2.5 inch diameter submersible pump and Simple Pump line… both inside a 6 inch casing.
Short and sweet of it was that by carefully pulling up submersible pump we were able to leave Simple Pump in place.
Checked: Simple pump worked fine post-removal of electric, deeper pump. This despite fact that when I put Simple Pump in about a year ago I had placed between PVC pipe to electric pump and electric feed line (where free, near top of well-head). But, this was no problem as these lines passed over the entire Simple Pump assembly at removal, as we planned to cut electric line to allow for easy removal and splicing once put replacement electric pump back down.
Exactly what we did. Hooked up new pump. About 100 ft. depth. Passed down casing carefully. Passed by the Simple Pump (about 60 to 70 ft deep) without any problems. Both pumps now work as intended.