Here is a site that may help answer some of the questions about Disney’s Magical Express.
Keep in mind that this is from the Disney meeting site so the information is for group travel. To book DME call CRO, DVC members book through Member Services. I thought it was interesting to read that Bell Service gratuities are included for luggage delivery to resort rooms. I would have tipped again.
I am not sure how often the site is updated but I have heard SWA has been added to the list of airlines. Disney didn’t confirm this, in fact, after calling I was told SWA is not one of the participating airlines.