1.) I don't know what the ship/subsystem limit has been upped to. Search feature here is broken. Search feature on FSW is broken. Hope of finding out limit right now...broken.
2.) You would be okay using the attack order with the GOD sat. It cannot move around like a transport or fighter, only spin in place. If you use the attack order, the platform should turn so that its weapons face the designated target. Alternatively, you could simply position the GOD sat so that it faces in the direction of attackers before hand in FRED2 without giving it any orders and, provided its weapons haven't been locked, it will pick up targets in front of it on its own and fire at them. In this case, it will not rotate to face targets however and will remain static in that regard. So if you want the thing to fire one way then acquire another target 90 degrees to its right with its particle beam and missiles, you'll need to use orders.