"Disney considers mousekeeping to be a non tipped position."
Certain jobs are considered tipped positions - like a waiter or a waitress. This means that they can be payed a percentage below minimum wage, and must claim their tips (I would guess that most claim some amount of tips but probably not all) on their taxes.
It doesn't really matter as far as I'm concerned that Disney considers Housekeepers to be a non-tipped position (meaning that they will have to pay them minimum wage). I'm not sure what the industry standard for hotels is, but if it was me, I would tip Housekeepers at a disney resort just like I would tip Housekeeprs at any resort anywhere. It is the customary thing to do. If I was at a Hilton or whever I wouldn't think to ask what if Hilton classifies the Housekeepers as tipped or non-tipped. I would just assume that you tip them at you normally do in the USA.
One thing that is weird about tipping at DVC, to me, is that they don't come in every day, and they have the light days for just trash and towel, and the room sizes can change. So we usually play a little by ear, tipping more than we would for a standard hotel room because it is fewer days, and more if it is a larger room, but sliding back if it is just trash and towel. Again, it would slide depending on service too. You just have to go by the feel of it. We usually go around $20 for a 2-bedroom and $10 for a one, because I think it is more time consuming to clean those accomodations. I think about that when I tip someone - am I taking up their time and keeping them from getting a tip from someone else.
About Valets. I don't know if Disney considers them "tipped positions" or not, I suspect they don't but I will tip them. I usually tip them at both drop off and pick up at a hotel; I know that it is customary to tip only at pick up, and I would do that at a restaurant or something like that, but at hotels I tend to tip both ways because I might never see the guy again because I may pick up the car on a different day. It is a different situation to me. That's just me though, ymmv. They usually appreciate it if you tip when you drop off.
I tip a shuttle driver a couple of bucks if I don't have bags or if he doesn't help with them, and a buck or two a bag if he does, whether in Orlando or any other city. If I take a town car or some kind of private driver I'd start out with 10% and think from there based on the service. I'd be in that neighborhood for a cab, with a consideration for help with luggage.
You tip a different guy for the bags than the parking valet. I tip the bell boy in the room for the bags. There are sometimes weird situations where the bellman might pick up the bags and you are checking them to pick up later if you have a meeting or something before going to the airport, so I'd tip the bellman when he picked them up, and the guy at the bell stand when I picked them up later. Again, I don't know if Disney classifies bell services or valets as "tipped" or "non-tipped" positions in terms of their tax status, but I don't really care and tip them like you are supposed to (assuming good service, of course). Basically, I'm saying I tip them at Disney like I would expect to anywhere, I don't see why Disney should be any different.
But that' just my opionin.