Well, any distance on the bike still counts, and nobody ever said it would be easy doing it with kids in a chariot!
Filzer products (for me anyway) have been hit and miss. Having said that, I don't have a kick stand so I can't speak for the quality. Since it's an MEC exclusive/in-house brand, it should be okay and you have their warranty.
Most, if not, all stock seats suck ass. I tend to steer people away from the MEC brands (i.e. Planet Bike etc.) and encourage people to go Italian (i.e. Selle Italia, Fizik, Selle San Marco, Prologo) and Specialized (American.) Again, you would have to go to a bike shop to get fitted, but try to put in more bike time before changing saddles. It could also be fitment between you and the bike that is causing problems.