|On your second post:|
If you want to keep the original files on your computer, unchecking them on iTunes wont delete the files after you sync again. iTunes wont transfer those photos to your iPad and you could always back them up. You will keep the files but not on your iPad. I am a Back Up fanatic so I BU every file I want to keep 2 or 3 times on different disks or devices and I recommend this practice to anyone.
You could create folders for different groups of files or photos and transfer/sync to your iPad using iTunes just the set, folder or Album you want on your iPad. Every subfolders is an album on the iPad after syncing.
There are commercial apps that will help you manage your pictures easily CopyTrans Photo will cost you $29. PhotoPod will cost you $20. These 2 don't specify the iPad but instead the iPhone OS, but this is the same OS for iPads.
On your 3rd post:
Not that I am aware if you choose the pics from "Saved Photos". But be aware only a sync can delete from the "Photo Library album".
Just to be sure and more specific:
When you get to the point where the top bar shows "Select Photos" and you select an image, a check should confirm your selection. And also the "Delete" button shows the number of selected files. After you select the ones you want to erase then choose "Delete". A second dialog "Delete Selected Photos" appears for you to confirm your action.
I am happy to help!!