"If a front panel is not displayed, do updates to indicators actually occur (other than those that are used as outputs). If so, can efficiency be improved by deleting these indicators? "
No they are not updated if not shown.
BUT, in term of memory allocation, if your unused indicators contain a lot of data, of either array or bundle datatype, then LabVIEW will give them memory spaces which in some case is intended to be avoided.
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