As the author of the NetBSD Wii and Wii U ports, congrats! I’m looking forward to seeing how you solved some of the problems that I faced along the way.
I wouldn't say "will never work". H5 is a Cortex-A53 and NetBSD can boot these just fine in aarch32 mode. The RPI2 kernel for example supports all models (32- and 64-bit) of Raspberry Pi except for the original.
Ditto. I had planned on porting FreeBSD to it, but with all of the delays and more interesting boards coming out since it was announced, I've lost all interest at this point.
Cubietruck definitely works! There is no pre-configured image, so you need to build your own. Easiest is to start with another Allwinner image (say the Cubieboard2 one), replace U-Boot with the one for your board, and add your dtb.
Look at ports/sysutils/u-boot-cubieboard2 for a template on how to build a suitable U-Boot, and sys/boot/fdt/dts/arm/cubieboard2.dts for a template for your dtb.
The article is a few weeks old now. One change since it was written -- Raspberry Pi 2 SMP support has been added to -current and is expected to be part of the 7.0 release.