Did your relative have such an odd way of saying a word or a phrase that a census taker or clerk would be hard-pressed to spell it correctly? The reason you are unable to find a name that's clearly written on a record could be because your relative had a highly unusual way of saying it and the clerk simply did the best he could. The problem is compounded if the clerk was unfamiliar with your relative's family and simply wrote what he heard. Clerks in small towns are more often to know what someone really means when the use their own unique pronunciation.
Today's post title is how it would have sounded if my grandmother had said "Use the bulldozer to push the multiflora roses in the manure pile."
The sentence I made up. The pronunciations I'm not.