The busybox library messages are normal. The busybox build uses a two pass approach to determines exactly what component it needs and which not. During this process it bravely reports what it does not need. These are there simply messages, not errors or warnings.
The parameters order in make.sh is indeed ot logical and this is a inheritance of the past. I ill havea look inhe coming days to stream line this.
dmesg can be enabled in the kernel, but this makes the image larger. I case of the atevio 7500 where flash space is scarse already, this is not a good approach.
As stated before, building as root is bad practice, as it bypasses all safeguards built into Linux to protect the system files in case of mishaps. If you still want to do that simply remove the test from make.sh.
Regards,
Audioniek.