A: Unfortunately, we're not aware of any affordable and/or accurate home tests. Here are a few things you can assume without testing:
Your plain, home brewed kombucha will be roughly 8 grams sugar per 16 oz. That is a pretty tried and true measurement, based off of an average 14 day brew. Just remember to account for any juice/fruit etc. you add in a second fermentation.
As for alcohol, it takes very highly technical brewing skills (usually brew masters in commercial breweries) to get the alcohol up over 1% alcohol by volume. They are manipulating yeasts, adding large amounts of quickly digestible sugars, aging brews, etc. For a home brewer like yourself, consuming your bottled kombucha within a reasonable time frame (3 to 4 weeks), you can rest assured your brew is at or well under the legal limit of .5%.