SI-7475 Pay the duplication tax for findMember/findMembers

Swathes of important logic are duplicated between `findMember`
and `findMembers` after this run of optimization.

    d905558 Variation #10 to optimze findMember
    fcb0c01 Attempt #9 to opimize findMember.
    71d2ceb Attempt #8 to opimize findMember.
    77e5692 Attempty #7 to optimize findMember
    275115e Fixing problem that caused fingerprints to fail in reflection. Also fixed test case that failed when moving to findMember
    e94252e Attemmpt #6 to optimize findMember
    73e61b8 Attempt #5 to optimize findMember.
    04f0b65 Attempt #4 to optimize findMember
    0e3c70f Attempt #3 to optimize findMember
    41f4497 Attempt #2 to optimize findMember
    1a73aa0 Attempt #1 to optimize findMember

This commit updates `findMembers` with the bug fixes that `findMember`
has received, and adds flashing warning signs for future maintainers.

A followup commit will address the duplication at the root.