I haven't got around to testing this:
https://1drv.ms/u/s!AvHY_kl4hMB4gQmqrT5rpI3vVSBY
For arm64 you need different preseed files (see earlier links).
EDIT: Sigh, you always spot a mistake when you post something without testing it...
release_ver=$(distro-info --series $PROJECT -r | awk '{print $1;}')
should be
release_ver=$(distro-info --series $SUITE -r | awk '{print $1;}')
Being pedantic ${LB_BOOTSTRAP_QEMU_STATIC} should probably be added to config/binary_rootfs/excludes