There are no plans to port Antenna Mate to Android. We don't have the resources and we don't use it ourselves. In the mean time you could take look at http://maps.antennamate.com from your Android phone. It's not as good, but it might help.
Ensure that automatic compass calibration is enabled. You can check by going to Settings > Privacy > Location Services > System Services (Scroll all the way to the bottom) > Compass Calibration.
Antenna Mate is not compatible with the WiFi only iPad because it does not have GPS or compass hardware. Apple only puts that hardware in iPhones and iPads that have 3G/Cellular.
Same as the WiFi only iPad.