Lookin' good!

I don't think you can really remove the unused cogs without changing the wheel. (?)

As long as you have to change the wheel, get one with a coaster brake, and move the caliper to the front. As you brake, your weight shifts forward, so that the front ends up doing most of the work. If you ever need to panic stop, you'll lock up the rear and not stop as soon as you'd hope.

Bikes don't get thrown out around here either. I live in a lower income neighborhood with a high Mexican population. If a bike is not totally hopeless, they fix it and ride it until it is. They haven't discovered oil yet, so the chains are always rusty and they just keep pedaling, squeaking away. That sound is like nails on a chalkboard to my ears.