Surnames do have their own meaning, much like Smith/Carpenter/Baker, but you don't really play around with them quite as much. I didn't give tones, so it can be written with any characters you like:

Lin: Forest
Zhen: Upright, Suppressed/Composed, Battle
Nan: Man, South

Mix and match and you could probably have Zhen Nan = Upright Man, for example.

Yu Ren Jia:

Yu has no meaning that I'm aware of, though originates from breath.

Ren: Virtue/Benevolent, Endurance
Jia: Good person, honored person

Ping: Even/peaceful
Zhi: Mountain, Order, Aspiration