7 days in a bucket with a freeze-thaw is not ideal. If you are going to reuse it you want it to be healthy. You could probably throw another beer in there and the yeast that are still alive would do their job. Although, why put 5 gallons of good wort through a sub-optimal fermentation? If it were me, I would collect a scoop and make a starter, then pitch that for the next batch.
Bacteria are the only culture some people have.