SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world.
And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download two short videos (registration required) highlighting:

System Workbench for STM32

Project doesn't generate .bin file



For question 2, you already found the solution.

Now, to answer the first question you need to know that neither the hex nor the bin are used in System Workbench to program (burn) the application.

In fact internally System Workbench - as it is gcc based - uses gdb and openocd to program and debug your application.
Thus means that :
- System Workbench passes the elf file to gdb
- gdb reads the debug informations to grants code comprehension
and extracts the loadable sections (same as in the bin file)
then passes these sections to openocd to burn them.

To conclude, the elf does not contains only the burnable image but others information (such as debug info).
And only the loadable sections are programmed, which is equivalent to program the bin, or hex file.

TIP : even the bin, and hex files have different sizes because the content is represented in different ways (+ hex contains adresses, but the bin does not)