The story of Leah is all in good time, Bee. However, she is 19.
The reason for the Jedi allowing Javen to resume his place as the Onderonian Prince, is because he is the only known child of the Royal family at this point. However, later we will find that there is another child of the true descendent of Freedon Nadd, the Queen of Onderon, who has just been killed.
Garzulan... ahhh, a quite complex character. While he is the owner of the Cantina, he is not the one who runs it, hence the barman that was a bit secretive. And to keep him extra protected, for he could not completely trust the barman so he enlisted a mercenary army.