I have a 23 hybrid. There are 15 screws that hold the cover under the engine. The cover tucks above the front and in the middle back. If it's tucked in correctly, it will hang there by itself with no screws. That makes it easy to reinstall the screws. It's an easy process if done correctly.
Yes, your battery is probably sulfating. Get a free battery before your three year warranty expires. Extended warranties don't cover it after the 3 years. A lot of people have this problem. Mines a 23 too, and it goes into sleep mode daily. I've had the battery replaced once. You might want to...
Mine came with a little of what yours has. My issue is that it wasn't trimmed very well. I had to clean up the edges myself. Not a big deal, but a little annoying.