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.

Go nuts.

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.

I don’t know, can you?