Is there any contemporary word(s) in English which would then mean "guerrilla warfare" committed by soldiers?
Asymmetric warfare can be conducted by either regular or irregular combatants, guerrillas or terrorists - this seems the closest approximation. Soldiers conduct "raids".
Yes, your one was basically correct. The co-operation with armoured elements was not realized before the year 1941
I used Combined Arms because I understand they also formed the infantry element in the Cavalry Brigade and didn't want to exclude that from the definition.
Finnish like terrain because we have only Defence Forces and not operate in plain open terrain
I disagree, I'm not talking about Russian Steppes or Desert but rolling countryside or, for example, when conducting Urban Operations even a large park, car park, airport or other open area would be better suited to armoured units than dismounted troops.
At unit level would not the "windswept plains of Ostrobothnia" be classed as open?
http://virtual.finland.fi/netcomm/news/ ... SAID=36461
Certainly South western Finland offers many opportunities for mounted manoeuvre as did areas around Lake Ladoga/Karelian Isthmus when they were within National Borders.
Thus, during the Continuation War, as I understand it, the Finnish Armoured Division was normally committed in those areas in which the agility and tactical capabilities of its equipment could be used to their best advantage.
Still, I think we've reached a solution on the HQ thing!