ZebraFinch, please consider pursuing the Foreign Service through the traditional route as well (i.e. FSOT --> QEP --> FSOA --> Medical/TS/Suitability --> Register --> A-100 invite). Moreover, if you enter the State Department Civil Service, you could be eligible for the Mustang recruitment program (QEP --> FSOA --> Medical/TS/Suitability --> A-100 invite) after achieving tenure. Best of luck!
Glad to hear you're applying for the Pickering and interested in becoming an FSO. Please consult the following link for tips, which are applicable to the Pickering Fellowship, on creating a competitive application (statement of purpose included): http://www.rangelprogram.org/index.cfm?areaid=2&contentid=911&mcontent=y&typeid=CBRIAP92223
Feel free to PM me if you have any additional questions.
P.S. What are you up to in Amman?