The main challenge with u-boot on Meson8 boards is that half the stuff you think you know hasn't been implemented yet on the prehistoric version of u-boot that's being used .. it's an archeological exercise
LE's KERNEL file contains an initramfs so we don't use a separate initrd file, and we avoid the entire topic of coexistence with other distros by simply not supporting it. As a rule it's not a big requirement on ARM devices among our userbase so we avoid the heartache.
wrxtasy released images for C1 for a while and I can see active installs in our stats server, so there is prior-art in his GitHub repo. There is also ongoing effort from dtech to adapt his LE 9.2.x image.
There is also a slow-burning effort to run mainline kernels on Meson8 boards. The amlogic-mx branch in my LE repo builds images but we did not figure out the u-boot bootscripts needed yet, so we are interested in what you figure out. Keep sharing infos.