Explanation

The key clues are:

“shifting ... between a rational, colonial voice and a fractured, interior consciousness”
“without consistent design”
“guided by no discernible principle”

These phrases describe something mixed together without clear organization.

miscellany = a varied collection of different elements, often loosely assembled
medley = a mixture or blend of diverse things

Both capture the idea of a narrative made up of disparate modes or voices rather than one unified structure.

template = a model or pattern: opposite of “without consistent design”
touchstone = a standard for judgment: unrelated
breakthrough = an important advance: not suggested by the critical description
debacle = disastrous failure: too strongly negative; the sentence emphasizes formal inconsistency, not collapse or failure

Answer: B,E