There’s really only one (functional) difference between Kit 1 and Kit 2:
In Kit 1, you have “Single Acting Cylinders.” That is to say, when you activate the piston/cylinder, air pushes the rod out. However, when you deactivate the cylinder, a spring returns the rod to the start position.
In Kit 2, you have “Double Acting Cylinders.” When you activate the cylinder, air pushes the rod out. When you deactivate the cylinder, air pushes it closed.
This basically means that Kit 2 closes faster and with more force than Kit 1.
It depends on its use, but yes. If you can use it to just push out then you should be pretty good. I like doing Double Acting simply because I enjoy powering in both directions, even though it is not always needed.
I recommend getting kit 2. Even if you only need air to push the cylinder out, if you were to get the double acting piston, you could tension the mechanism with rubber bands to give it a little extra power. Also, having double acting pistons for different mechanisms are nice. You’ll be wanting them in the next years to come.
It should also be noted that you will get about twice as many actuation with Kit 1 vs Kit 2. This is because air is used to open AND close the cylinder in Kit 2. However, Kit 1 only uses air to open the cylinder.
I believe there are some other similar threads, you might want to have a look for them they might be useful.
My personal opinion on which to pick - for the extra US$50 get the double acting kit. You can do the same with the double acting ones as you could with the single acting ones, just only put air in through one direction. And the best bit is, if you only want to use air in one direction, you can choose WHICH direction gets air powered. You then just use rubber bands to do the work for the other direction of motion. Also by buying the double acting kit you are future proofing your team, which is perhaps the most important thing.
For the sakes of a high goal scorer though, you probably don’t need pneumatics. You could do something like 4886A, using the rope to pull it over, but my personal favourite is the way I saw one of the Asian teams doing it at Asia Pacifics. It was so simple. All they had was a platform, with a lever, so when they drove into the high goal the lever was pushed, tipping the platform. The other way is to just use your normal intake to do the high goal scoring, if you are still using a design which can reach the high goal with its intake (assuming your new robot HAS an intake I suppose… ;)).
For easyC, use the Digital Output block under the motors category (I believe), in order to control the solenoid. Also, be sure that your controller configuration is set to Output for your solenoid. (See this thread)