AA is the most obvious choice for flight selection from Dallas (WN from Love is mainly good if you have shorter flights and care only about free flights instead of status perks).

You can check the rental car company web sites to see which car companies' cars are most heavily represented at each rental car company. For example:

Hertz: Ford (including Mazda, Volvo, Lincoln in their premium collection, and the Mustang GT-H special-for-Hertz edition)
Budget: Ford or Hyundai
Avis, National: GM
Dollar, Thrifty: DaimlerChrysler

However, all of them do have some other-company cars in their fleets, so there is no guarantee that they will give you the desired brand of car (but you can improve the odds by choosing the rental car company whose fleet is heavy with the brand you like).

For hotels, if you know where you are going, find out which chains have hotels where you are going. Note that Hilton, Marriott, Intercontinental, and Choice have various brands of hotels to choose from.