Then it sounds like a fixe set up to offer two different ratios.

You wouldn't have to put a lock ring anywhere, that's what's probably there to keep things from humorously unscrewing themselves while riding.

If you look at your blurry top picture, left side of the hub. First there's the bigger sprocket, then there's the smaller sprocket. Then just outside that is what I just can convince myself that it looks like a ring with a few notches cut into its circumference. That'd be the lockring. It even appears to be a short part of hub base material protruding outside the (assumed) lockring, which gives you a fighting chance of determining thread direction.

If my interpretation of the blurry pic is right, then some careful introduction of Mr Hammer and Mr Drift Punch, or possibly Mr discarded Screwdriver to the notches will take the lockring off.
After that the sprockets should come off with a chain whip. There are ways of improvising around that if you haven't got one.