What marQ said.
This can be challenging. Depends on the intended use of the recording. If for a competition, you probably should leave it (after bringing whole file up so that peak is around -0.3). If for general consumption (not necessarily audiophile), then I’d bring levels up. Typically, I set markers and then slice the files up by song in Cubase. I then open each song in Wavelab. Step one is to bring up the file so the loudest peak is at something like -0.3ish. Check the loudness. WL does this with the LUFS scale, which is a handy way to look at loudness. You can use RMS as a substitute if you can’t get to LUFS. It’s not unusual for the initial unprocessed file to be in the negative 20s LUFS for loudness. This is just too quiet for most people. I use the loudness normalizer in wavelab to get the file to approx -17 LUFS. This usually makes the song listenable in a variety of environments, but still retains a large dynamic range.
Classical music can be tough to get under control. Depends on the piece. If there is a lot of quiet space and then some massive percussion hits later, you’ll need to consider other options beyond just loudness normalization. First step would be hard limiting to pull the transient spikes of the percussion down. Second technique would be using volume envelopes - this is tricky and should only be done if it can be finessed so as to not be noticeable. Usually a combo of hard limiting and loudness normalization does the trick for pieces that have a wide dynamic range.
My ultimate check is in my car while driving. I pop in a cd (or an mp3 on my phone) of the songs in and turn my volume up half way. If I can hear everything, then it’s good. If not, I consider tweaking. Also, as I’m adjusting loudness, I try to do the adjustment and then listen to the result. If it negatively impacts the piece, then I undo it and try something different.
EQ - Probably not needed with the mics you’re using.
Reverb - need to listen to determine if any is needed. If needed, I lightly use the built in reverb in Cubase - Reverence.
I would break up into songs, rather than having one giant file. Doing fade outs of the applause for each piece is a good idea. I often do fade ins as well if there is room noise that is audible at the start of a song. This way the listener isn’t jarred by the sudden onslaught of room noise.
You’re on the right track!
-Tom