I don't know much about Manzanita, but I have been there. I remember thinking it a pretty typical small Oregon coast town.
I know nothing about schools or growth for it, sorry. I do know that the coast in general tends to be a better vacation spot than living area - weather cold and wet, schools small and not usually the greatest, living generally expensive...this might not be true about this particular town, though.
My advice would be to take a road trip, spend a few days there looking around, visiting the school, checking out the available property, etc. Try to go during the week, I'd say.
Visiting is probably your best bet for getting a good idea about the place.