Unfortunately, no - all of the bases have onion (as well as most of the sauces - except possibly the creamy herb). That said - the onions are finely chopped, not excessive and, at least personally, I’ve never really been able to taste them (and I usually have sensitivity to onion in food). Of course, I know that for many people “no onion” is nonnegotiable no matter what - so that might be a dealbreaker for your family if the other options (like the pods or hot dog) aren’t a sell either.
I believe the slaw is vinegar-based - I’ve never noticed mayo (and I don’t like mayo at all - so either it’s not there or used so lightly that I couldn’t even tell).