Question about REHABILITATION OF OFFENDERS ORDINANCE?

The following rules apply when deciding whether a person qualifies under the REHABILITATION OF OFFENDERS ORDINANCE (ROO):
1. that he / she must be a first time offender at the time of committing the crime
2. that the punishment of the crime did not exceed a fine of HK$10,000 or a prison term of not more than 3 months
3. that the person does not commit a crime in a period of three years after the sentence
So to answer your questions:
2. If your friend was a first time offender when she committed the shop-lifting crime in 1984 / 1985, and she was not sentenced to a fine of more than $10,000 (or sentenced to jail for longer than 3 months, which, somehow, I do not think so for such a minor crime), and that she has not re-offended, then she would qualify under this ordinance and can legally not disclose her criminal record.
1. However the ROO does not apply to people applying for some positions such as the law-enforcement / disciplined services (eg. police, immigration, customs, correctional services, icac), the judiciary (which includes barristers and solicitors), professional positions such as accountants etc. So your friend cannot be a solicitor or barrister. But at the moment in Hong Kong a Litigation Clerk or a Legal Executive is not a "regulated position" - ie. it is not regulated by law and do not require professional recognition from regulatory bodies.
So the answer is YES your friend can still be a Legal Executive.