It really depends on your hardware, there are many systems with limited storage and memory where Fedora is impossible to fit. I do believe Yocto is the Gentoo for embedded linux, which is over-engineered to hell. The good news is that, unless you have some very special requirement, just use buildroot, which is 1/100 of the complexity and get the job done well. KISS.

Using a package manager on an embedded system is just asking for trouble. Or read-write rootfs, for that matter.

I usually have a r/o rootfs as squashfs with overlayfs for changes. It makes it easy to wipe things back to factory defaults.