spin recovery procedures are the same for all planes. Yes, harder to recover for some, actually harder for ww1 planes as you say, probably because of relatively thin airfoils, but nonetheless, exactly the same for all planes, old or modern.
Not really...
As an example, modern jets usually requires "stick inside turn" for an efficient recovery (using induced yaw of the applied roll moment) instead of rudder (who may be masked from relative wind, and thus unefficient).
Some alternative as the "standard" procedure also exists (and are more efficient) for stable airplanes (with strong enough dihedral angel).
I still agree with you that for WWI planes, the only efficient procedure would be the standard "PARE", since the rudder will generally be much more efficient than ailerons on these planes... except for planes with too rear-CoG, that would in most case not recover (like Camel with full tank for example).
Heavy engine at the front end, flimsy wood and wires behind. Turn off the engine and the plane should drop nose-first like a stone
That's a common missunderstanding of the WWI pursuit planes aerodynamics... most of them were rear-centered (sometimes a bit too much like the Camel with full tanks).
You must remember that the more rear-centered a plane is, the more manoeuvrable he is (and that's exactly what the designers wanted to do... they knew empirically that rule). A forward-centered plane would be clumsy to fly (more stable, less prone to spin... but there were not reasearched qualities for pursuit planes...), with large turn radius, etc....
