Star Wars Galaxy of Heroes has been out for over a year now and in 2017, there are more hackers and cheaters than ever. This may be because of how easy the game is to exploit without using dedicated spoofer. Any online shard generate can easily spit out unlimited resources at will.
You can also max out your characters including all abilities by using the iPhone hacks that are designed with no jailbreak or cydia usage in mind. Simply use it without activation code and you can unlock Zeta Vader: one of the most sought after characters in Star Wars Galaxy of Heroes.
For Luminara and Yoda, you can follow the popular mods tutorial to access these characters in an instant. You do not need to memorize all the strategy in the game to farm Shards. In fact, all you need to know is the proper route to get more crystals which is explained very well since the release of the game. Farming shards is a controversial issue because of how time consuming it can take. Now, hackers can get their hands on a lot of shards and crystals fast. Faster than most human players can do.
This is not fair and has yet to be fixed until yet. So to play Rey as your character, use the unlock features of the tool.