Welcome Han!I'm not aware of any developers working on the F1C100s, but it is a very interesting SoC and I would love to have it supported in NetBSD!
1. The generic kernel is adopted for ARMv7 series chips, if it could be used for ARMv5 series chips, as there are many common used parts for suniv and the other sunxi chips.
The generic startup code currently only supports v6 and v7. You will need to add support for v5 to sys/arch/arm/arm/armv6_start.S
2. The FDT device tree is working for generic kernel now, if we have procedure for apply this for the other chips and boards, like mini2440/imx2 series evaluation boards, includes my futher work for suniv f1c100s.
Currently the GENERIC kernel is v7 only. You can still take advantage of FDT in other kernels, as demonstrated by NetBSD's RPI kernel.
Given the limited RAM in the SoC, you probably don't want every driver under the sun included in your kernel image. The existing sunxi device drivers can be adapted for use on F1C100s though.
I hope this helps! Jared