That's right, ships with jump drives can go through them without a gate(and can also bring a certain number of non jump ships in the same task group along with them based on your max squadron size tech and the maximum tonnage of the jump drive.) and jump gates allow ships without jump drives to travel through the gates. Just remember when you build a gate it's one way only, so you need to build another gate on the other side to make it 2-way. 2 way jump gates make the lines connecting systems on the galactic map yellow as well, making it easier to tell what system non jump ships have easy access to.
Officers and commanders give bonuses to what they are assigned to do. Naval commanders for example can give % bonuses to ships. Like having a captain on an asteroid miner with a mining bonus improves the mining output. A captain of a survey ship would benefit from a high survey % bonus. Also note that there are dropdowns all over the officer screen. For example changing the warships dropdown to staff offices allows you to assign a fleet command admiral, and once you have one of them you can assign his staff officers.
You can also switch from navy officers, to ground officers, to scientists, to civilian administrators. And in the civilian administrators you can assign governors to entire colonies which apply all their bonuses to their colony's output.
I don't know what some of those bonuses do though. I don't know what logistics does for example other than it is good for your fleet commander to have it. And from what I understand political reliability is intended to do absolutely nothing but waste points and make a few less useful soldiers get higher ranks because they are "The governor's nephew" or something like that.
I'm afraid I don't know how to move around the queue, I always just deleted something If I decided I want something else done first. All the ones that have been done are already built and available and the ones that haven't been done yet haven't cost any resources yet. So all you lose out on are the non whole amounts.