Mu Lung Training Center(Dojo) Guide

Interesting... I'll need some time to fully understand it, since I didn't really know anything about dojo before.
If a party defeats a certain boss, do all members of the party get the same amount of points as someone who soloes?

No. Party PQ gains half the points of Solo per round.

So what I'm wondering is do they spawn often?

That depends on the boss. A LOT of the bosses don't spawn the monster frequently, which makes it very difficult at bosses like Pap.