I am probably odd man odd out here. If I understand correctly, you have culled a design of your own from various sources. Presuming that is correct, the following are my thoughts. A) sooner or later you will run out of the fabrics you are currently specifying and therefore, your 'design' will change predicated on those specific fabrics. B ) you have already stated that your design is, for lack of a better term, 'loosely' based on another. I don't think the original creator could 'come after you' since there is (apparently) 'little' resembselance (sp) to the original creator; C) I don't know that you could continue your 'original' design simply based on the fabrics.
Again, I am probably odd man out in the belief that once you purchase something (design; pattern; etc) it is yours to do with as you please. Certainly to the letter of the law, you may be prevented from 'sharing' a pattern or design, my belief is that once you purchase it is yours to do whatever. Not unlike persons who have purchased various books and donated them to a local library. Once that transaction has taken place, those books (regardless of subject matter) are now in 'the public domain' and can be copied/used to the renter's discretion.
I am sure others with more detailed knowledge of the subject matter will weigh in as well. Good luck.