The aerobatic aircraft I've seen don't have any flaps or air-brakes, besides they're taildraggers so I guess they usually have to do stall landing or three point landing but I don't understand how the pilot controls the approach speed or just how they slow down.
The same as any other powered aircraft would - controlling their descent with a combination of pitch and power.
Most small GA type aircraft don't have air brakes, spoilers etc anyway, so that's fairly immaterial.
I'd imagine almost any civil aircraft can be landed quite safely without flaps - it certainly forms part of the standard training syllabus for the PPL and you'd likely be expected to demonstrate a flapless landing on your skills test. The only difference is a slightly faster approach and more nose high attitude.
You can land all planes without flaps etc.. It's just the question, if it is a landing or an arrival
In crosswind situations, a lot of pilots prefer to do little to none flaps set, as the plane stays more controllable.
Btw. you can slow down the plane by pulling the nose up. Putting the nose down increases the speed. This helps to adjust the speed.
The plane slows down from aerodynamic drag. Level off above the runway ( also referred to as the "flare"), and wait - the plane will slow down by itself, as it does the wing creates less left, and the plane will settle down to the runway. Holding the nose up as that happens helps to create drag and slow it down.