My post is lost :/

I went into bit more detail...

short version:

Scotttyd
There are two ways of using train with Lufthansa:
1. You buy a ticket xxx-FRA and add an auxillary product Rail&Fly (30EUR 2nd class/60EUR 1st class)
2. You buy a ticket xxx-FRA-ZMU (Muenchen Hauptbahnhof - Munich Central Station). This is Express rail

1. In case of Express Rail you pick baggage up in the AiRail terminal. In case of Rail&Fly it's regular belts.
2. LH suggess 1h is enough, I would say that's optimistic. ~2h +- is what I would go for. Depending on when exactly you arrive, there's a train at 7:34 that might or might not work.
3. You do immigration in Frankfurt. All things considered, you are likely to beat the train into Munich, but not by much. Expect about 1:30-2h from door open to central Munich.
4. Express Rail is for a given train. Rail&Fly is for any train on a given route.
5. You should be able to select if you want 1st class when adding Rail&Fly to your tickets.
If you get 1st class Rail&Fly, you will get seat reservations for your chosen train when checking in for the train. You can still take other trains, but without seat reservations. 2nd class does not have reservations.
Express rail 1st and 2nd class have seat reservations, and you have to take the train you are assigned, if you miss it, you have to ask to be rebooked as if it were a flight. For Express Rail, which class you get depends on your flight ticket.