Uses of hua- in Levanto's catechism (1732)

I have been trying to understand the prefix hua- in Colonial Valley Zapotec.

Here are some examples from Levanto 1732 showing differences in the syntactic distribution of verbs with the stative n- or imperfective r(i/o)- and the same thing preceded by the pre-aspectual hua-.  In both main clause question and response we see hua- here:

Levanto 1732, f18

But notice in this pair, the question is n-aca while the response is hua-n-aca:

And both are n-aca here:

And both are rapa 'has' in this example:

In the following, hua- is in the main clause while the same verb is without hua- in the relative clause:

Here we have hua-rapa in the affirmative but rapa in the negative:

Tentative hypothesis: Naca is the neutral copula;  hua-naca emphasizes the duration.  (In some cases it might be translated 'is and continues to be').  Similarly rapa is neutral 'have' but huarapa  emphasizes duration.