Hi Sally,
I think that you have most of the bases covered in terms of stores (Target is not on your list but I am assuming that you shop there too). On accasion you could try Marshalls / TJ MAX but they are hit and miss at best.
The best way to keep informed about what is currently in the stores is to keep checking this site, many members post what they are finding on the shelves regularly.
Regarding your list of needs, many of these are still available in stores (Grem, Nigel, Shu etc) some are not yet released ( Taia Decotura, Taco Mater) and some are just released and so either the stores don't have them yet or are holding them until they sell what is on the shelf (Prince, Don, Bindo, Officer etc.) and if you can wait they will eventually hit the shelves if not then this site or Ebay/Amazon will be your best bet.
You should also add your e-mail to your list and if you have cars available for trade or you are simply buying so that members can tell you if they have what you need available. (Some memebers here could probably fill most of your needs at leass than Ebay costs.
Also there area couple of great resources on this site than can help with some of the rarer/hard to find cars. If you need some help with this I can share their e-mail and you can reach out to them. I can be reached at dewing99@hotmail.com
Dave.