Locals and NPC
 

What's the differences...other than one is local and one is NPC. What are the advantages and disadvantages?

Also...scheduling problem...2 houses I want to check out have their first party at the same time...after that, the times do not coincide, but informal seems to happen over the same weekend, and I don't just want to go to one house's informal recruitment and have that be it. How should I work out my scheduling issues?

Do a search for the differences on locals and NPC. There is a ton already.

I'm not sure but I would go to the beginning of one event, leave halfway, go to the next. If one starts earlier do that first, or if one goes later do that one second. Just make sure you see both.
Good Luck