Let me help you out here,

6. One of the horses parked in front of the saloon is actually a bear. The joke is all these tough cowboys are getting thrown out of the bar. Who would be bad enough to do this? Clearly whoever is bad enough to ride a bear to a saloon.

4. Lucy was the name of the oldest known fossilized remains of a human. The joke here is the 'second' Lucy also found in the same region, is also Lucy from the comics. There's multiple layers to this cartoon. It's a play on the name given to the earliest person found, and to imply everyone in that ancient region would be named Lucy is hilariously obtuse.