How long does this jam last? Is there a way to do it in a waterbath canner to last longer?

I can't tell you the absolute lifetime of this jam- it's never lasted more than a month or so at my house because everyone loves it as a snack item. However, it contains sufficient sugar and vinegar to preserve it in the fridge for many months, kept in a covered jar. If you wanted to process a larger batch in a water bath canner, you certainly could. A half pint or pint jar would only need 10 minutes of boiling time. Using a commercial metal lid to seal it should leave it shelf stable and safe for at least a year and actually longer.