Hi, I Could do it in 3 Days. It seems like Pocket Beagle board with adding of more functionality, backed up with MCU,GSM module, USB port, and powered up with Switching PSU.
Lets Discuss about this design furthermore to make this design finished. Once it finished, I would do this Design.
I have experience in 4 layer PCB, high speed design, USB, BGA fanout, and differential signal like USB, Switching Power Supply, and I always follow recomended design guide from vendor when design a PCB, So, you don't have to worry about it.
Best Regards,
Rijal