4) wheels mfg and some amazon vendors sell “valve stem savers” – essentially grommets to plug the Schrader hole in your rim to fit a presto instead. Please use these instead of drilling your rim – that can have catastrophic results.
5) Not exactly sure what your riding in Ohio, but Id assume your running 2.25′ tires? If your looking for cheaper, but good options Id look into IRC tires or Onza tires. Both have good build quality, but will be about half the price of an equivalent Maxxis item.