LB refectoring on the path to persistent LB instances

[PhilMiller]

What Needs to be Done?

Work on #965 is in progress, but incomplete. There's a bunch of refactoring to be done to get there that should get merged sooner rather than later, to avoid bit rot and integration consternation. This issue is to give something for the corresponding PR to be associated with.

Is your feature request related to a problem? Please describe.

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