1) Was Warsaw a training Center for SS Battalions ? (Such as Dachau had a SS Training Depot)
Yes. At least 2 W-SS training and replacement battalions were stationed there. There were troop training grounds in Lublin, Krakow, L'viv and Warsaw
2) What SS Regiments/Divisions would these units have been assigned to-if they had not been
used in Warsaw Ghetto Rising?
They were training and replacement battalions for the 3rd SS Panzer and 8th SS Cavalry Divisions.
Arnhem was the location of an SS NCO school. During operation MARKET-GARDEN, "Kampfgruppe Kraft" formed around SS AuE (Training & Replacement) Battalion 16, which would have been for the 16th SS Panzergrenadier Division