"Do we need to rake up the dead grass before we plant? What is the best way to plant the wildflowers? For our front yard, if we plant drought resistant grass, do I have to remove the dead Kentucky bluegrass first? Also, are wildflowers and native grasses bug/slug resistant?"

First, you need to make sure the grass is actually dead. If it's still alive you will start seeing some growth when the temperatures start to warm up (about March). If this is the case, allow the grass to grow up a little in early spring and then treat it with Round-Up. Either way, you will need to remove the dead sod before you plant your wildflowers. I would suggest broadcasting the wildflower seeds and then raking over them to make sure they are covered. It will be important the first year that you control the weeds - this will cut down on the possibility of future weed problems. Once you get the wildflowers established, they will have a much better chance of out competing the weeds. In general, native plants do tend to be more insect and disease resistant.