I wouldn't go cutting your steerer tube just yet. That's something you can't come back from. And the spacers do serve a useful purpose from what I can tell. You can just transfer the ones from below the stem to above it unless your stem was all the way at the top of the steerer with nothing above it.

I thought about doing that. There's a cap with a hole for the bolt to go through so that it's not just a tube sticking out. But with what I've done, not sure if it lowers my posture enough, and putting ALL the spaces above just looks silly. My thing is, all the pictures I see of other FCRs, none have those spacers. So why is my bike different, and is there a way to buy a different tube, or is it permanently attached to the forks?

have fun riding the hell out

Plenty of people have bikes with the spacers above its just to test things out in your case so just do it and ride. I tested out an FCR likely the same year and model as yours and it had plenty of spacers so I don't think yours is special. In any case its probably good to have it longer because the worst case scenario is you have to get it cut.

Don't do any cutting just yet. Give yourself some time to be sure it's what you want. Kind of a "measure twice and cut once" deal.

As for the cramping--be darn sure you are taking in enough fluids and, if you are sweating a bunch, potassium/sodium like has already been suggested. I believe that cramping in usually a sign of lack of minerals. Also, the stretching will help.

As for the derailleur adjustment: it, along with things like fixing a flat and adjusting brakes, can be learned by watching YouTube videos. There is a ton of good instruction on there. For me, I have to be able to see how it's done before I can learn it. One word of caution: for any repair you want to learn, watch at least 2 or 3 videos. Most of them I have seen are fine but occasionally I run across one where the guy is teaching something completely wrong. If you watch a couple and they agree on how to do something then you should be fine.