Trait Info

Reward Version does not appear in the Create A Sim mode. It is for people who don't want them to appear there and also to add as many traits as they want in gameplay mode. NPC Sims spawned by the game will NOT be randomly generated with traits of any of the Reward Version. You may prefer to install the Reward Version for traits that you don't want to see a random townie get. 

Original (CAS) Version appears in the Create A Sim mode. It's easy to use but there's a limited number of CAS traits a Sim can have. NPC Sims spawned by the game will be randomly generated with traits of any of the CAS Version. 

For 100 Base Game Traits V1: No, you need to choose either one.

For V2 and other trait packs of mine: Yes, you can.