dev0 Unfortunately, after wakeup, keyboard, trackpad and trackpoint were dead and could only be recovered by a reboot. Only the screen resumed correctly from sleep. Does this mean that the device ihidev0 is somehow associated with these input devices?
No, the system failing to resume all devices correctly is a bug and should be reported as such. As should ihidev causing a suspend failure.
(Suspend/resume is very spotty on NetBSD: Thinkpads generally work because the devs own them. Plenty others don't. My current one, for instance, completely locks up on resume: even the screen remains off.)
dev0 Are there any additional settings that need to be put into /etc/powerd/scripts/lid_switch to cause correct resume of the input devices?
You could try resuming the keyboard/mouse bits there:
drvctl -Q pckbcN # keyboard controller
drvctl -Q pckbdN # PC keyboard
drvctl -Q pmsN # PS/2 mouse
where N is the number you get from a drvctl -lt
