If a hardwood floor is properly installed and finished there is no way you'l get splinters from it. Soft woods such as pine can splinter but here again proper installation and finishing will minimize it. Hardwood floors are minimum maintenance, especially if you remove shoes when entering. Carpet is expensive to install and is a high maintenance item if you wear shoes in the house. The squeaks in the floor indicate that it wasn't installed very well. Subfloors need to be tongue and groove and need to be glued and screwed to the floor joists to insure they don't loosen and squeak. Too many contractors cut corners and just nail them down. Nails easily pop loose over time and cause the squeaks. Carpet may mask some but will not eliminate it.

No.. the squeaks are usually caused by two things either the subfloor isnt secured to the joist tight enough or the subfloor is rubbing on the nails used to hold the floor down. the only way to eliminate the squeaks is tighten the floor down. either by going under and screw it down or from above and fill the holes in and restain and seal.

Yes it will muffle it a bit but not at all get ride of it.

I am intending on buying a house from a family member and it has hardwood floors almost throughout the main floor and they squeak pretty bad. I am not a huge fan of wood because i have gotten splinters in the past and it just seems hard to maintain a good glow to it so i thought why not carpet.