Salvageable! Check the soil, it might need to be repotted, especially if the soil is dry and/or compacted. Other than that, water roughly once a week and keep it in a sunny window.

You can also take a cutting and put it in a glass of water as backup. Make sure to get at least one node (the wider area in the stem, usually with a little nub of aerial root starting). Cuttings with leaves attached will have an easier time.

I'm no expert by any means, but I've seen plants come back from much worse. It's worth a try.

Absolutely not, it’s just a bit leggy. You can either cut the individual pieces and replant them in dirt and they should sprout roots after a while, or you may be able to put them in water for a while (this method takes longer). As long as there isn’t any rot anywhere

Not too late. Clip off the spindly bits. Two options: cut into a few sections, it turn in water until they root then replant. Or, cut it into sections where there is a node in each section. Lay the sections flat across the Silk with the node facing down. Water lightly - like with a spray bottle every day until the nodes root and leaf. You can put cinnamon on the cut ends which acts like a fungicide. It you can find root growth hormone I find it helps jumpstart the rooting.
Good luck!