I wouldn't attempt to merge LGNPC together, much less with anything else. Dialog and script-heavy mods really tend to go wonky if they're merged.
Yup. People have attempted to merge the LGNPC mods before, and it's ended...rather poorly. Sticking with the unmerged versions is your best bet, even though there's a lot of esp files.
If you're worrying about hitting the hard-coded esp limit, OP, it's around 240 or so--pretty hard to hit unless you're doing some hardcoe modding. And FWIW, I use the LGNPC mods and NoM and a whole bunch of other mods and only have 188 esp/esm files.
If you do need to merge mods to save space, I'd recommend merging smaller, less complicated mods together rather than trying to merge NoM or LGNPC.