Hopefully, someone with more knowledge will chime in, but in the meantime here's my 0.02 (as I've done some very minor plumbing jobs in the past):
1) If you can buy a replacement hose + end piece for your particular model, then that should do it for you. You probably won't have much luck swapping in another model / brand, depending on the model you have. You'll need to research your model and see if they sell the hose and end piece as a separate part.
2) I'd go with a mix of brand and value. Moen is pretty good, so is Delta. Avoid Koehler. YMMV - read some online reviews and go for simplicity. We have a Koehler Elate that has a little button underneath to pause the flow and it kept getting stuck. We swapped out two under warranty before finally figuring out that we shouldn't use that button at all unless we wanted to have at it with the needle-nosed pliers every so often.
3) You'll probably just have to replace the faucet if #1 above is not an option. No need to replace the hoses or fittings unless they are leaking or corroded.
Finally, you can get a 3-hole replacement fixture but you would just have to drill two new holes. Easy to do if you have laminate counters - less easy (more scary for DIY IMO) if you have granite or quartz. Always easier to do two extra holes than to scale down from three holes to one, though I think you can buy a plate to cover the extra holes if you ever find yourself wanting to go from three holes to one. That might depend on the fixture, though.