"as long as you give proper credit due"???????????????????
So, who is going to decide what is original and what is not and what is in the public domain?[/QUOTE]
"Proper credit" means that you have to advise what pattern you used and who designed the pattern. Often this is put on the label. When in doubt if using a specific pattern then give credit.
Also Solid means NO pattern even if it is a tone-on -tone. If in doubt clarify the rules with the organizers of the challenge. All of the fabrics that you posted look like prints to me!!!