Here are 3 different uses of the freewheel with chainrings. (And now I wonder if there is a name other than "chainring" for the steel discs; I have to admit that can confuse me too.)
1. Single steel "chainring", in this case mounted on the left side of the bike and motor driven. Freewheel allows motor and chain to be stationary while cyclist pedals. If the disc-type chainring is threaded, then the unthreaded freewheel holes are utilized; and vice versa.
Same architecture with smaller "chainring", in this case providing a considerably taller final gear.
2. Dual steel "chainrings" (one driven by a motor, one driving the rear cluster), mounted on right side of bike for fairly inexpensive setup but losing the usual triple front chainring feature and requiring movement of the motor-chain when pedaling (presumably there would be a freewheel at the motor shaft). Here we can use the non-threaded holes in the freewheel flange if one of the chainrings is threaded. If both chainrings are threaded, then one of them would be drilled out to remove the threads. We used a spacer between the freewheel flange and one of the chainrings to make room for both chains in simultaneous operation.
3. Triple chainring setup (utilizing custom spider):
The parts, showing a 74/110bcd 5-arm custom spider. The middle chainring is centered over the freewheel flange, while the granny and outer chainring are balanced on either side. Not shown is that more recently we combined the two custom parts into one, so that granny and middle/outer chainrings are attached to a single custom spider.
How the parts fit together.
Finally here are the 3 chainrings mounted and fully operable on the right. Here we used a "64"/104bcd 4-arm custom spider but with a custom granny whose inner diameter cleared the freewheel shoulder.
This is our power integrator, not yet in production, that shows left(motor) and right(cyclist) freewheels, and with a single chainring on the left and a triple on the right. The concentric drive in the BB allows the motor to drive the chainrings through the BB from the left side of the bike without the cyclist having to pedal, and for the cyclist to drive the chainrings from the right side without the motor chain spinning.
The custom freewheels can be had for $15 plus shipping. We're working on making available the custom spider and concentric drive.