Does either a "leasehold" or "long term occupancy" alone and without consideration, covey any type of "ownership interest" ?
Generally, no. A leasehold gives one the exclusive right to possess property and the long term occupancy presumably is similar. Even a 99 year lease does not convey title, though it may have many of the attributes of ownership.
Employment / Labor Attorney
The interest conveyed by a lease or long term occupancy agreement is generally governed by the agreement it self.
A person/entity often records such an agreement with the county recorder in order to notify the "rest of the world" of the interest. This action may stop third parties from coming in and ousting the person/entity with the recorded interest.
However, such agreements normally do not convey an "ownership" interest in the property, although some of the rights to the property may be quite similar to ownership rights.
I am licensed to practice in Nevada. Please note - the information I post is not legal advice and my response does not make me your attorney. If you would like to seek my legal advice, then please contact me directly. I participate in AVVO in an effort to assist people by providing general answers to questions. However, you should always consult an attorney (meaning talk with one face to face in a consultation) before taking any legal action.