As I understand it Jesus gave his last speech, the Great Commission, during his resurrection - in about year 30-36. In this speech, he proclaimed that the Christians should seek to spread his word to all peoples of the earth.
Here come my questions;
If Jesus said this to the disciples why was Paul seemingly the only one doing it? Who else (except Pauls travel companions) also preached to gentiles who just aren't as known or recognized in the bible as him?
They were hamstrung by bigotry in the early years. It was difficult for them to understand that Jesus could be for even Samaritans, much less gentiles.
This is seen in the issue between the Hellenist and the Hebraic Christians in Jerusalem and continues through the first part of Acts when we realize that evangelists like Phillip and those in Antioch are
Hellenists.
There is negative dynamic that occurs within a minority community that is trying to assimilate into a hostile majority, and we see that dynamic in Acts. That's what's occurring in the synagogue of the Freedmen (Hellenists, because "freedman" is a Graco-Roman concept. There is no concept of "freedman" within Judaism) who turned in Stephen (one of their own) to the Sanhedrin in order to curry the favor of the Hebraic Jews.
Saul, also a Hellenist, was a wannabe into the Hebraic Jewish society (from a wealthy, established Hellenist family--that amazingly still knew their tribal heritage and Saul was haughty about being a "Hebrew of Hebrews"), and as people in minority groups can tell you, there is often nobody more savage than a "Judas goat" of your group who is trying to gain favor with the majority.
That's why we see Saul ravaging the Hellenist Christians but leaving the Hebraic Christians alone. For instance, if he were really trying to destroy Christianity, why after assisting in the stoning of Stephen (a Hellenist) did Saul next travel all the way to Damascus rather than chasing down the (Hebraic) apostles in Jerusalem? The people who had to flee from Saul were the Hellenists, as were the Christians he was heading to Damascus to capture.
But we see the Holy Spirit leapfrogging the Hebraic Jews, getting beyond them to Cornelius and the Ethiopian Eunuch (in fulfillment of Isaiah 56)--people the Apostles would not have willingly gone out to, except by the Holy Spirit forcing their hands. Even then, it was the Hellenists who most quickly and boldly carried the gospel beyond Jerusalem.