Well, I thought I had the flashing figured out, but after I began flashing, I got errors about the archive not containing boot.sig and recovery.sig. Did a Google search which said I should be able to ignore them, but the entire process stopped and didn't go any further.
It always warns about those files missing when using Google's flashing script, but that's fine, and it should keep going after that. How long did you let it sit? Some parts take quite some time, and it might seem like nothing is happening.
Have you made sure you have the latest Platform Tools and such installed in the SDK Manager (if you're doing it that way)?
does flashing erase data i.e. music, texts, etc.?
Yep.
Yes but you can skip the wipe by deleting the -w from the script. I flashed from the first preview to the new one without wiping and haven't had any problems on my n5. I don't know if it causes any problems coming from KK.
Yes, but DON'T DO THIS if you're coming from 4.4, you will have issues (from the first L preview to the second is probably fine).
Also, if this is your first time flashing something onto the phone you're gonna have to unlock the bootloader first, which will erase all user data anyway.
Can the members who have flashed the developer preview report back the battery use on the n5?
And is there any caveats to installing the developer preview? Will it still update OTA to the final build?
Haven't been using it for long enough to judge the battery life yet, will report back when I feel like I can say something interesting about it. But I will say that I definitely experienced an improvement with the first preview over KK.
But no, the dev preview won't get an OTA update to the final release. Gonna have to flash again once that's out, to get back on the OTA train.