A Cycle Analyst is not a controller display, it does not communicate with the controller in any way. See the Grin Tech info pages on the CA's to see exactly what they are and do, and how they hook up, before considering one.
Regarding actual controller displays:
Displays are specific to controller brand, model, and sometimes even version. There are no standards for connection or communication. Or you can say that everybody has a different standard, that they themselves don't even always follow. Same result.
So you'd have to see if your controller matches any of the ones already posted about (or otherwise known elsewhere) to work with the specific display you want to use.
Even if it does, there isn't any guarantee that it will do more than turn on and off from the display, it may not show any data on the screen from the controller (just the defaults in the display), and the display may not be able to send anything (settings, etc) to the controller.
You'd also have to know for sure what the wiring of the connector on your controller is--if you just hook stuff up you will almost certainly destroy the display, and probably the controller too, because there is battery voltage *and* data lines on the display connector--mix them up or connect the two types together even for an instant and POOF, then it's time to replace everything because you can't fix it (no parts available).
So the only good / easy way to put a display on a random unknown controller is to replace it with a display/controller kit that comes together, so you know they will plug into each other and you know they can talk to each other.
Then you want to be sure that not only does the controller do what you need it to for your system, but that the display will actually display the specific things you want to see in the way you want to see them, as you likely can't change what it shows or where, how, etc.
Regarding speed sensors--you'd have to check if the specific system you're interested in can use a wheel speed sensor, because as you note they typically use motor halls, and have no plug for a separate sensor. The display does not do anything other than use the data from the controller to display on screen, so the controller itself would have to have a separate plug for the sensor.
If all you want is a speed display, there are cheap bike computers / speedos that do that with a wheel sensor. If you want something more, you'd need to know exactly what it is you want to see, before you go looking at displays/controllers, to make sure they can show that.
