They sure can remove it, but it will leave a big hole on your window, which you need to "patch up", which generally they may not able to do it.

Those contractor doing renovation one.
Basically you patch up with a window.

Alternatively, just buy a plywood, paint it and nail it as cheaper version one.

Less job for contractor...
Very common, just tap the existing line, then job complete, instead need to take out the wire from the starter/contactor, and need to install a switch for it.

If already preinstalled and concealed, there is nothing much you can do, except you want to hack it and change the piping.
If not R22 may still around for the next 5-10 years time.
I don't see R22 is going to be phased out so soon as currently there is still plenty of new air-cond with R22.

You can't worry something in the far future that nobody can assure of.

Nobody can guarantee R410 will be last forever as well.
Technology changing, regulation changing etc which you never can assure of.