In order, yes, no, yes. Err, sort of.
Could they have?
Well, in the short term, certainly. If they’d attacked the Imperial troops with X-Wings (and whatever other fightercraft/armed vessels they had at hand) instead of the underpowered speeders which they “had difficulty adapting to the cold,” they could most likely have mopped up. At the very least, using the faster spacecraft would have let them approach the Imperial Walkers from a direction other than “right where all the damn guns are pointing” before the base was overrun. In addition, they could have started peppering the orbiting Star Destroyers with that mongo Ion Cannon right from the start, keeping them disabled, or forcing them to land troops even further away from the base. But then the fighters wouldn’t have been flight ready again in time to escort the evacuating troop transports, before enemy reinforcements arrived. They’d have been overrun on the ground by the next wave of Walkers and troops. The Imperials could have also simply moved their own fleet out of range of the cannon, and lay in wait further along the “evacuation route” from the planet, given the extra time. Flying past two disabled (or at least surprised) capital ships, with small, fast and fairly manuverable ships, is a lot easier than getting those same ships through a cloud of waiting enemy fighters, with properly deployed capital ships as support.
Did they want to?
In that sense, no. It was, as you stated, a delaying tactic, and not a serious attempt to hold the base. But, realistically, yes, they wanted to hold off the Imperials long enough to scoot out the back door.
Did they actually win?
Going by all this, yes. Of course, winning a battle isn’t quite the same as a successful withdrawal under fire, but they did achieve thier goals.
Far as I could tell, that’s it in a nutshell. They used the fleet (probably the flagship itself, up until the attack on the second Death Star) as the new base of operations. Somewhere near the planet Sullust, according to onscreen dialogue.
- A bunch of ships in orbit over an inhabited planet is easier to spot than a hidden, mostly underground base on an out of the way planet no one in his right mind would want to go to
- George Lucas isn’t much of a military tactician
- Dramatic License
You make the call.