Hello!
I would sugget that you perform a "best price search" on the Lufthansa website. It will show you the best prices over the next months. I would also monitor the prices a while. Prices may considerably vary. As you are flying in a long time, you still have time.
There are different fares, the lowest in PE being N. Of course, not all seats are available in N.
To my knowledge, the front row PE get a foot rest attached to the seat (like in C).
You will probably not get an offer to upgrade to C, but you can bid for an upgrade (from your reservation page).