What build are the people who are finding Port harder than Retail FS1 (Please let me know this!)?
I can only really recommend you pick up a very recent nightly to test, as a lot of AI behavioural problems in the builds after Sushi's AI profiles post effected FS1 in missions with Avenger/Shields much more harshly than pretty much any other mod.
As far as I can tell (beyond missiles ...and who cares about missiles?) there is very little/no appreciable differences between Port and Retail because I had a similar complaint when I started playing it, I did however flesh out the problem quite a lot, and came to the conclusion it was some SCP based changes that had effected /everything/ not just Port.
...Most obvious in port? Yes, but not Ports fault.
As for the mission, on insane the only realistic ways to do this mission is to do it the same way as ST:Rs escape pod mission.
You memorise the warpin points of the enemy fighters and have your fighters on c37 while you sit behind said warp in points in order and then hit engage enemy as they come in.
The HoL ships /ARE/ saveable, however you have to be quite trusting in your AI to look after the convoy (can't remember which cargo container it is, but if you order the ai to protect the right one and are burning to the HoL/Vasudans before it arrives then you can manage it, I actually think I remember you having to swap which cargo container your ai are protecting on the way back too).
If you don't want to bother flying all that way and back, you can let the convoy die to no ill effect,
- you can also steal a fighter from it (well on retail anyway, I imagine on port too but I haven't checked).
It's very doable and as far as I know only the AI general problems (most, of which have been fixed, seemingly? (I need to confirmness)).
But yea, good luck it's a very tough mission to get a 'perfect' on (note; you don't need to save the Vasudans).