Non-Composer needs help with famous score

Hi everybody.
I am trying to make a recording of L.v.B.'s 5th sym using my electric piano, sound module, and 16-track recorder.
I am an intermediate pianist, and can read music, but I am stumped on a few things with the score.
After reading many posts, many of you seem friendly and experienced enough to help me out so here goes:

1. I have a line for "Corni in Es." Is this a cornet in E flat? That is what wikipedia suggests. Symphony No. 5 (Beethoven) - Wikipedia, the free encyclopedia

2. The key signature for the Corni has no sharps or flats, as compared to the regular 3 flats for C minor, but the G-clef is in the normal position. Is this saying to play E flat where a G is usually written? Same issue for "Clarinetti in B" and "Trombe in C".

3. Is a cornet the typical instrument used today? The closest my sound module gets to my recording of the LA Phil is with the French Horn.

4. The string section on the first page has 5 lines: 2 violins, viola, cello, and bass. Then on page 2, there are only 4 lines written (one of the bass clef lines disappeared). Does this mean that cello and bass are playing the same line, or that one has dropped out?

This is the score I am using: http://www.sheetmusicfox.com/Beethoven/besym51.pdf

Thanks for the information that anyone can provide.

Patrick

1. "Corni in Es" is the Horn in Eb. All notes will sound a major sixth lower than written.

2. Older orchestral horn and trumpet parts frequently omitted key signatures, since the instrument had no valves and therefore could not play outside of the harmonic series. "Trombe in C" is a Trumpet in C, and it will sound exactly as written. "Clarinetti in B" is the Clarinet in Bb, the notes will sound a major second lower than written.

3. See #1 above.

4. Most likely the basses are doubling the cellos. If the basses are to drop out, there will be some sort of text indication that states that.

Thanks for the reply.

If I may follow up on #2 (and show my lack of knowledge!), for the horns in Eb, how do those sound in terms of higher/lower than written?

for the contrabass staff, you might notice on page 2 that there is a little text marking "basso", which means the contrabass will share the staff with teh celli until otherwise indicated. however, it is important to note that teh contrabass appears to be doubling the cello ONLY where there are stems in both directions (3rd through 5th measure of page 2). The rest appears to be ONLY the cello section.