Has there been any recorded cases of http://www.nexusmods.com/skyrim/mods/8429/? or http://www.nexusmods.com/skyrim/mods/36334/? being unstable, causing lockups or CTDs? What about when run together?

Both are very popular and are often run together so I highly doubt it. I'm running both since quite a while without issues. That said, mods adding NPCs add up so if using both with several other mods adding NPCs, there can be issues.