A. – Brendan, the issue here is the fact that you’ve actually used the sample in the work you have created. If the end product is so different to the sample purchased in the first place, then what was the purpose of using the original sample? Clearly in using the original sample, you have derived some value from it by using it in your own end product, notwithstanding the fact that the original sample may be unrecognisable in your end product.
The fact that you do use samples in the creation of new work clearly indicates to me that the original composers of those samples should be entitled to be compensated. By way of analogy, it’s a bit like a builder arguing that he shouldn’t have to pay his supplier for cement because the cement can’t be seen from the outside of the building. So long as the sample used is capable of attracting copyright, any use by a third party of the sample should be subject to standard licensing arrangements.
This is a case of ‘swings and roundabouts’. Bear in mind that if someone uses samples of your music you will be entitled to compensation from them!