- Stopping a current (voting) survey to add a new question
- Re-activation of the survey; and
- existing token holders to vote on the added question without disrupting previous questions they have responded to?
What does "disrupting previous questions" mean?
To add a question, you need to deactivate the survey. You can reimport response data and participants list.
Depending on where and how the additional question is added to the survey, I would expect different effects. Depending where the token respondents are, the additional question might not be shown.
I recommend you just check the procedure of deactivating, adding questions and reactivating a survey with the LimeSurvey version you actually use.
It should work, but certain versions can have bug, preventing the procedure.
Depending on the legal implications of such a vote, I cannot recommend to do it that way. You cannot be 100% sure, if voters have seen the additional question in every situation.