1) All of the named parliamentary units come into play only via event cards?
2) you simply cannot use them without being unlocked by an event card?
This is a bit confusing with how the rules are written
"You may commit any available Named units you desire to your (Parliamentary) side of the Battle Display Mat."
if they are available!
I thought they were readily available from the start of the game...no wonder these battles have been going fairly easy
Yeah, that's an unintentional house rule that would make battles easier, all right.
3) If being unlocked through an event card only , are they from that moment on always available in future turns? (if not being lost by deadly outcomes)
Right (unless they die or some event explicitly removes them etc).