[Mobhack]

1) long range SAM have a very long minimum range usually. Thus they cannot usually target on-map fliers (helos and planes that made it on map without a shot at them while approaching). So they will generally only fir at planes making a stand-off missile attack, or on their approach run. And if you moved them they wont be ready to fire in any case.

2) Buk wont cover anything on map. Also they need to be stationary in order to fire. They wont fire if moved, and the same will probably apply to the Zsu-57 - they will likely decide the chance to hit is too low, even if they have shots left after moving. Zsu-23-4 would generally fire (even if moved) since they have so much better FC and they have radar so are not bothered by battlefield smoke which does bother the radarless units like the 57-2.

3) In a User campaign, the designer decides how much repair points you get. he obviously expected you to not need much, or its designed as a campaign where losing stuff means they dont get replaced. Check the briefing, or post a message to the scenario designer on the "scenarios and campaigns" sub-forum, the designer may be still around and reply.

4) The campaigns provided are what is commonly available. There may be some in the campaigns sub-forum that have not made it into the releases, but its unlikely (other than say WIP campaigns).