I'm a Computer Engineer with 7+ years of experience in low-level development, and have done quite a bit of work on ARM-based MCUs such as Texas' Hercules and Piccolo series, and Sitara AM335x (BeagleBone Black). Most of my work consisted on drivers and lower-level IRQ handling code for the RTEMS RTOS, though I've done some bare-metal driver work as well.
While I don't have an STM32 device myself, I've done this kind of embedded work remotely in the past and it shouldn't be an issue as long as we maintain a good level of communication and have someone from your team available for testing. Chat me if you want to have a call to discuss the details.