Go nuts.
Yes why not. I've used paperclips and even solid core network cable strand before as well.
If it fits it sits.
Seems fine in a pinch. Everything is so low (voltage and current both) that I don't think it matters too much. Plus breadboards imply temporary tests. If you're doing something more permanent like a breadboard CPU like Ben Eater then probably not.
I don’t know, can you?
We'll see I guess
I believe in you, let us know how it works out
Can you? Yes
Should you? Probably not. High resistance and bad contact
Yeah, that ought to be fine. Breadboards aren't rated for fast signals or large currents. So not really a concern.
Network cable is a good cheap source of jumper wires. You can also save the bits of tin that you clip off various components -- over time you'll end up with way more than you need. These are easier to bend into shape.
You know the wire-reinforced plastic strips used to secure plastic bags with twisted ends like the ones sliced bread is sold in? Just used four of these in a project.
