Theoretically it is possible to start the engine under the stated conditions ,if you press the EMER GEN TEST switch . When you press the EMER GEN TEST switch you are able to power 28V DC EssBus(4PP) by batery2 ,and battery1 powers static inverter and static inverter 115V AC powers AC ESS Bus (4XP) and static inverter bus 901XP..
If these buses are powered you can get power for IGN A, Captain PFD/ND and Upper center display unit E/WD , other LRUs related to engine start are also powered.
Make sure your batteries are in good condition. EMER GEN TEST switch is momentary contact switch,you should keep it pressed till your start is complete and you power the aircraft with engine power(IDG).
This is not an approved procedure and you should follow the approved AMM and FCOM procedures to start the engine.
Never experiment with aircraft systems,follow approved safe procedures and practices.
If this was asked in a oral interview to test the knowledge of the candidate, the above explanation is theoretical answer.