Was /data mounted correctly when you pushed the rootfs? Did you format userdata? Also, you seem to have overlaystore enabled but overlayfs in kernel is not enabled (unless I missed something).
Anyway, it is better for you to ask in t.me/ubports_porting, there are more knowledgeable than me people there that can help you, and real-time communication is preferred because porting can take a long time to succeed.