Currently I have two 3-way dimmer switches controlling a ceiling light. I want to replace the ceiling light with a fan/light. So I bought a Harbor Breeze fan/light. What type of switches do I need to buy that will allow me to dim the light from either location and to vary the speed of the fan from either location. In shopping around I learned that a 3-way dimmable fan/light dual switch is non-existent, but I did find a Lutron dual single pole dimmer fan/light switch to replace one switch, but what should I get to replace the other switch, a single pole on/off switch or a 3-way on/off switch? Or Neither?

On a 3 way, you can only put a dimmer on 1 side. Use a single pole 3 way on the other side. Fan speed is the same way.

You absolutely cannot do what you want without extensive re-wiring. There is nothing you can simply buy.

My recommendation would be to get a fan with a remote and get an extra remote.