I realize it was already answered but i figured i would go into a bit more detail per your questions earlier.
1. To defeat DS, you must have Red Squadron in the space flight w/ DS and imperial fleet, Red Squadron CAN NOT die before battle is over, and therefore you obviously have to win the battle. But you can not tell luke to attack the deathstar.
2. Heros can travel in the deathstar or capital ships, but most of the time they are given there own shuttles. (ex: c3p0, obiwan, emp(certain times) or any minor heros like field commanders...have there own shuttles)
3. Luke is part of red squadron only...FOR NOW...dont let this detur you from getting the game, b/c the expansion coming out in the fall will have both luke and yoda as playable ground units...and luke can turn invisible!!!!!!!
4. This game doesnt have "battle for hoth, battle for naboo, etc etc." the whole point of this game is that YOU get to decide how YOU would have fought the battle. So you CAN fight on hoth (in campain you would have deathstar by now, so unless you wanted to fight for sentimental reasons, just blow the %#@@ out of it lol), but there is no set "battle plan" that needs to be followed.
5. This one seems to have gotten skipped before. The choice between mon cals and ISD's is a hard one to make and really, it all depends on how well you can command your troops. "The best team is the one I am on" But personally i think that the moncals far outclass the ISD b/c the mon cals have boost power to shields and the ISD only has a crummy tractor beam.(something im not happy about) BUT THEY BOTH get OWNED by bombers
6. For EAW as it is released now, you CAN'T decide where to place your structures, BUT, again, in the expansion coming out in the fall, you can decide where to place structures...so again, dont let this detur you from buying the game.
7. As the game goes, YES!! you can use small fighters.....I say this because i consider the Rebel Snow speeder(air-speeder or w/e) to be a fighter...It flies, it fights, it shoots....its a fighter right? Also, you can call in bombing runs with bombers (which are small fighters in space :-/ lol) and in the EXP. you will be able to orbital bombard the planet with your ships in space