What's up with my data in iTunes?

When I want to sync my iPhone 4S (8GB), it tells me I'm over capacity by nearly 260MB. I want to ONLY sync music from my computer; no photos, videos, apps, or anything else. However, I know that iTunes already tallies up that particular data that is already on my phone. Therefore, I have (checked on my computer and already on my phone) 212 songs (1.40GB), 16 apps (1.44GB), 1.68 GB of Documents and Data. And 220MB of "Other" all ready to sync. The problem is it says I have 84 photos (1.60GB), when I'm syncing 0 photos from my computer and I only have 42 photos and 4 videos on my phone.

*Update: As I wrote this, my iPhone synced and I suppose it unchecked or changed a few things to sync successfully. I now says I have 192 songs (1.36 GB), 42 photos (1.57GB), 15 apps (1.41GB), 1.68GB of Documents and Data, 55.3MB of "Other" that is synced or ready to sync.

So I have a few questions:
1. What is "Other"
2. What is "Documents and Data"
3. What's up with my photo data during that sync I mentioned above?
4. What's up with that "Other" data during that sync?
5. Does this seem like a normal amount of data that only 42 photos can take up?
6. How did I lose 28 songs during the sync?
7. I've gone through and deleted all unnecessary photos, videos, files, apps, etc. That I didn't want or need. So what's on my phone now is essentially what I need, but it takes up So much data. Is this normal?
8. Either way, what can I do to free up more space?

Added (1). And I forgot to mention in the update that after that unexpected sync, I ended up with only 2.1MB of free space.

That's why apple and itune sucks. You should complain to apple and see if you can get songs. Also, you should backup media on the computer to external or different sub directory.