various memory leaks reported by valgrind (indirectly lost: 2,109,600 bytes in 1,978 blocks)

ran valgrind --leak-check=full during mutations and rebalance in/out of nodes

==23434== LEAK SUMMARY:
==23434== definitely lost: 100,931 bytes in 232 blocks
==23434== indirectly lost: 2,109,600 bytes in 1,978 blocks
==23434== possibly lost: 789,932 bytes in 196 blocks
==23434== still reachable: 447,506 bytes in 409 blocks
==23434== suppressed: 0 bytes in 0 blocks
==23434== Reachable blocks (those to which a pointer was found) are not shown.
==23434== To see them, rerun with: --leak-check=full --show-reachable=yes
==23434==
==23434== For counts of detected and suppressed errors, rerun with: -v
==23434== Use --track-origins=yes to see where uninitialised values come from
==23434== ERROR SUMMARY: 23704 errors from 101 contexts (suppressed: 24 from 7)

assigning to Matt for some initial review and feedback.

valgrind report attached..