All right, tested what I thought, you're right Mr.Smith - the AoE suppression's definitely dependent on the main target's cover rather than ignoring cover entirely.
mg42 rush into buildings vs USF can be fatal in the early game, if there is an effective counter I don't know it, smoke requires grenade package which is 25 fuel, delaying your Lt. and also requires vet1. If anyone could offer some effective strategies to deal with this it would be really cool, and much appreciated.
This is not true, only the upgrade is required for Rifle MK IIs and smoke.