The English class system is a tricky thing, and knowledge of the fine points of the rules was one way to tell who really belonged from who didn't, but here are a few notes.

] OK, the genteel, or gentility, did not "work", but lived off the income from estates or interest on their "fortunes", correct?

The ideal was to live off the income from inherited land, and the longer it had been in the family, the better. The next best thing was to have some other kind of "private income." Since there were very few stocks or private bonds at that time, a private income usually meant having money invested in government bonds ("the Funds") or having a banker or lawyer invest it for you in mortgages.

] For the second and younger sons, was it for them to go into the clergy or the military? Do these two professions allow the person to remain "gentlemen" ?

The next best thing was to draw a salary for some kind of public service. The Forces and the Church were both considered genteel professions, as were the higher public offices. (Note, though, that Members of Parliament were not paid).

Are there any others? Mr. Phillips (in P&P) is a country lawyer, and therefore, a "bad connection" to Elizabeth. Are city lawyers also not gentility? Mr. Wickham studied toward being a lawyer--would he then have not been a gentleman?

There were and are two different kinds of English lawyers, barristers and solicitors. In JA's time and for long after, barristers were the only ones who could appear in court, and all judges were appointed from among the barristers. Because of its direct association with the courts, the bar was considered a genteel profession, although not as much as the Forces or Church, and suitable for a gentleman's son. Barristers were drawn both from the younger sons of the landowing class and from bright young men of the lower orders. Wickham was supposedly preparing to be a barrister. George Knightley's younger brother, John, is one.

Solicitors (Mr. Phillps or Mr. Sheppherd in Persuasion) were most definitely not genteel, whether they practiced in London or smaller towns. Solicitors could not appear in court. They drew up legal papers, investigated cases and engaged barristers to try them. They also frequently served as business advisers or managers to their clients. A successful solicitor could become quite wealthy, but he would be considered to be "in trade" in the same way as a wealthy merchant. In JA's time and long after, a reference to an "attorney" meant a solicitor.