Emorse,
About foam for an emergency landing: There are dedicated runway foaming machines (usually using the old blood and guts method) as well as the fire fighting foam machines (using synthetic foam).
If you use up the fire fighting foam that's not such a good idea. Don't know about GVA but in ZRH there is the dedicated machine (I needed it once).
Also, a study is available showing no aquaplaning on the old type of foam.
Hope this helps.