Thanks Juvela for the mechanical tip re the crank arms!
On the hub barrels there is a logo I don't recognize, but it includes an "M" in a circle.
I could not find a marking on the upper head lug but will double check when the light is better.
I'll fix those pedals for the sake of posterity, but will likely swap in something that works for me.
Sadly, Tumbleweed is no longer in business....