Remove any alternative resolution in data handlers

The following discussion from !685 (merged) should be addressed:

• @graven started a discussion: (+1 comment)

  At some point, all the alternatives should be removed from the individual algorithms, and moved into the data loader -- as loading data from storage is the only legitimate case of alternatives that I can think of, and is the subject of !422 (closed)... (the main work is in updating the configuration, which we have to do anyway to benefit from the scheduler/broker)