I'd tried that previously, but did so again just in case it'd help. Before doing so I installed the new 8/29 updates for all components.
Unfortunately, I still have no cooler lighting.
I have noticed, however, that if I try to apply Static color to the strips, it also removes the effects from the ARGB fans. I wonder if somehow the "addressable strips" are conflicting with the ARGB header.
I think Armoury Crate/Aura Sync need to be able to control the two RGB headers on the board separately. It looks like the ARGB header "wins out" and the ARGB commands are confusing the RGB device, so it gives up and does nothing.
It looks like I may need to replace it with this
(the Tower 100 only supports 120mm coolers), but not having a lot of luck finding a reseller other than one dodgy "ships from China" entry on Newegg.com.