Yes, DPD and DFD are both on conventional UHF channels (the list is in the RR database here -->
Dallas County, Texas (TX) Scanner Frequencies and Radio Frequency Reference). Please note that there are rumors that they'll move to a new 700 MHz P-25 system (
Dallas P25 / NCTCOG Trunking System, Dallas, Texas - Scanner Frequencies), but it's not 100% clear if that will just be for interop, full operations, or both. For this (and other area agencies you may be interested in), you may want to start saving for a digital scanner.
Plano, however, is P-25 digital. Richardson is currently EDACS and should work with the Pro-95, but they're close to moving to their new P-25 digital system as well. Carrollton/Addison/Farmers Branch are on the Carrollton Public Service System which works well on my Pro-95. Lewisville (a bit west for you, but probably easily monitored) works well except for one channel (due to rebanding, which the Pro-95 won't support).
Look through the RR database for the area agencies and see what you can get. There are lots out there with good listening on a Pro-95.