The following force ability trophies can be farmed during the Prologue with Vadar:
Lightsaber Throw Mastery
Force Push Mastery
Force Grip Mastery
Force repulse Mastery
As you get off the elevator and move along the platforms (past the bridge that was taken out by a TIE Fighter) you will come to two bridges. Cross the first bridge and, on the platform on the other side of the second bridge is an (almost) endless spawn of wookies. Stand at the beginning of the bridge and just use whatever force powers you want. As Vadar you can not die, so don't worry if the wookies start getting in some hits. With this you will also get the Bossk trophy relatively quickly.
After you knock out the first mastery trophy, your best bet is to restart the level and work on the next one. I found that after about 30 mins the spawn numbers begin to dwindle until you have no one left.