Probably not, as I don't have one myself and no knowledge of it's workings.
Did you try the new RPi build, is it still panicking?
Take a look at /storage/.config/emulationstation/es_systems.cfg to see what platforms are configured for Emulationstation. There are some missing systems, ScummVM, ResidualVM and Dosbox. This is due to the nature of these emulators as you can't simply point them to a ROM file. I've been meaning to add a menu that launches each of these, but haven't had the time to investigate user friendly ways of doing this yet.
I didn't understand your transparency issue, perhaps you could be more detailed and/or provide a screenshot.
You may update the RetroArch cores through the core downloader in the menu. Keep in mind that in doing so, the cores you download will override the ones I ship in the updated images. The buildbot cores from Lakka may have issues because of the different toolchain used as well. As for other systems, the only way to update them are through upgrading to a new image. This is the nature of LibreELEC as a read-only squashfs.