SU25 Steps in Greenfield Implementation (Migration from ECC)

We are following Greenfield implementation for migrating to S4 HANA from ECC. And we are also transporting all the roles from ECC to S4HANA. In this case what is the best way to execute the SU25 steps. Is it compulsory to execute step 1 and then step 2 also in this case or can we transport the USOBT_C and UCOBX_C from ECC to S4HANA and continue with step 2. What will be the best approach in this situation. Please immediate response will be appreciated