Those are the reasons the owner gave you? I don't mean to be negative but, the only reason we ever put an embryo in a registered cow is because she hasn't produced show quality animals after being mated to several different bulls.
I don't see a reason to ever put an embryo in a heifer, we only keep heifers that we think are good enough to produce show quality animals, if she were good I would look for a calving ease bull rather than loose a year on a fullblood heifer.
I wouldn't take a chance on anything that isn't 100%, there are bred cows out there all over the place that will produce for you, why pay for someones bad leg? And last but not least, why spend money with someone that won't spend $27.00 for your peace of mind?
I know you are anxious to get your feet wet, but we are going into sale season, there are thousands of good productive cows that will sale in the next few months, why buy ones that you aren't comfortable with?