As for attacking and defending.
Finnish army is divided in to two parts: regional/territorial forces and operative forces.
Differences:
Operative:Newer equipment, more military grade motorvehicles, have most AFV, younger reservist, higher professional to reservist ratio, no specified area of operations.
Territorial:Older equipment, mostly civilian vehicles, have some AFVs, fewer carreer soldiers, defined area of operation.

Objective is to use territorial forces to deplete attackers formations, while operative formations are used in well timed (counter-)attacks to destroy or defeat weakened enemy, or atleast this how it is on the paper.
Btw, I remember having seen a basic Jaeger Bde TO&E on an official Finnish website about a year ago. At that time I was negatively surprised at the low survivability of arty/mortars and ATGWs (towed 120mm, TOW).
There are two jaeger brigade 90 left on wartime rosters.
I wonder where he got that information, because when I tried to find info in finnish for JGB90 with cats and dogs I found nothing whist there can be found organizations fo Infantry brigade 80, Jaeger brigade 05, armoured battlegroup, mechanized battlegroup and new territorial battlegroup

On survivability.
There are plans to replace towed mortar company with AMOS platoon in two southern jaeger brigade 05 and northern Jaeger brigade have their heavy mortars mounted in NA-122 all terrain vehicles.
Maybe it somewhat compensates their (indirect units) immobility and low survivability to use larger and dispersed formations.

Also finland has armoured artillery but not much. two armoured battlegroups have battalion of armoured howitzers and there are some separate selfpropelled artillery groups directly under corps.
At the moment only mounted ATGM system I know of is X number of TOWs mouted on NA-110 ATTV and they are used as corps level anti-tank unit.