When replacing carpet, can you re-use the tackless strips

Carpet will be cheaper to have installed, but the life time is much shorter than hardwood.

Look into strand bamboo. I believe it is much harder than any other hardwood and not as susceptible to humidity. I used it in my house on the most of the main level (about 1,500 square feet) and have been very happy with it.

Because it so hard, it is more difficult to install, so you may pay a little more for installation.

I don't know if you can ever avoid all creaks, but most can be avoided by putting down rosin paper first and nailing into the floor joists as much as possible.

UPDATE 1

I'm talking specifically about strand bamboo. Regular bamboo is much softer and scratches a lot easier.

Nope, your carpets weren't installed correctly. I'm not sure if code dictates that tack strips need to be replaced, but at the minimum, your contractor should have checked if any tacks were poking through or would otherwise pose a needle hazard. Those things hurt.

Shedding seems to be normal. We recently had some carpet installed on our basement stairs, and some corners (and manually-cut straight edges) do have the little plastic strings hanging loose, and several nylon curlicues roaming around. I really wish all installers would properly vacuum their junk up, but most of them don't.

Carpet on the steps does not necessarily have to be a single piece, simply because you can start a new piece (and stop the old strip) where a tread and riser meet. As long as the edges are butted together with no gaps, you should be fine.

Also, simply vacuuming should not lift carpet edge off (anywhere, specifically not stairs!)... that alone should require that they come back and fix it, or pay for a professional to re-do the effort.