Regarding the ISO thing... it's really just like film (or supposed to be), where a 400-speed film would work better in low light than 100-speed film, if that helps you get a handle on it. Since this is your first digital, maybe you're more used to thinking that way? (And a DSLR is a great way to start off in digital!)
But that brings me to a question: If I am taking a picture of something that is far away (or small), is it better to use the 50 mm f/1.4 lens and plan on cropping or use the 200 mm lens at f/5.6?
It really all depends on the light... if you're far away enough that you need the extra reach, you'll probably be best with the 50-200mm at 200mm. If it gets a bit darker, you can do the same but also turn up the ISO to get the shutter speed down. Once it gets dark enough that even at the ISO 1600 (or 3200 if you dare, it might not be as bad as you fear) you still are getting blurs from camera shake, you will have no choice but go to a faster lens.
If you're closer to 50mm, say 75mm or so, you might get a better shot with the 50mm F1.4 no matter what the circumstances are, due to the
very nice image quality of it. At some point, the extra quality is outweighed by the need to crop it too much, though, and I don't know if there's a hard and fast rule on that - it's really just something you'll learn with some experience.
However, the 50-200mm is no piece of junk and you should still be able to get very nice results out of it, so don't feel like you
have to use the 50mm F1.4 whenever possible.
Oh, one other thing... looking at your photos again, the second-to-last shot, with the jester, may benefit from some white balance adjustment. Indoor photos under tungsten lights often get a yellow tinge to them, and adjusting white balance can help dramatically, including a shot like that one where it may not be so obvious that it's got a certain color cast. The tricky part is that one also has outdoor light, so correcting the white balance for the foreground may through the background out of whack, but it's worth a shot.
The photo above it, of the picture in the frame, may also benefit from white-balance adjustment. All the others look like they're using natural sunlight, which usually comes through just fine.
Adjusting white balance on a JPG is a little tricky, that's one of my favorite reasons to shoot in RAW mode - it's easy to adjust that while converting them to JPGs.