2019.1:
If DISTRO_FEATURES are not modified you should have all backends packaged in the rootfs. Now, you can switch between muliple backends using update-alternatives commands as follows:
To Update a link:
update-alternatives --install /usr/lib/libMali.so.8.0 libmali /usr/lib/fbdev/libMali.so.8.0 90
To remove a link:
update-alternatives --remove libmali /usr/lib/fbdev/libMali.so.8.0
For more info, perform update-alternatives --help
Alternate solution: Users can always modify links using "ln" commands