RobinHood im guessing that means you actually watched most of that video
1) Zero Hour adds 3 different tears of each faction, ie there is an airforce general for USA. things like that. Its exactly what an expansion pack should be, an expansion of the original game.
2) I learnt that when playing my mate back home that he builds super quick, so in order to stand any chance against him, you need to get an army as soon as you can or he will own your base.
3) I never even noticed that my buildings were disappearing because of tats until he said something.

4) If you right click and drag when you are moving the units it shows you that ghost style thing so you can line them up
you can also hold alt to set a path for them to follow, for example going around the tiberium
the issue with playing generals is that you would defiantly need the cd crack for that because ive had file mismatches in that before, so it might not be worth it.