I know folks who,live on long, gravel roads who undercoat to reduce noise and dust. In the old days undercoating prevented rust also. Today vehicles are rust resistant and UC makes them tough to work on. I'd pass.
As for the other two, I've never bought either. On a new car, I wash, clay bar and put on a good coat of Meguires wax with a dual action polisher.
Buy your own quality paint protection product and do it yourself. I use Chemical Guys Jet Seal on my car about twice a year. The stuff is expensive - $39 per bottle - but a little goes a long way so the bottle really lasts. You do not need a da polisher, just some good quality, soft towels, which I also get from Chemical Guys. There are other products out there as well.
Like mentioned above undercoating and rust proofing is only worth it if you live in a snowy area and if you park outside.
Even if you have a garage you can park it at night, there's no need for rust proofing, since the snow will melt off.
Keep in mind that rust proofing and under coatings can get really messy, so if you will be working on your pathfinder at some point, you'll have to deal with all that.
I hate rock chips. Federal regulations required paint hardening chemicals be removed from automotive paint some years ago and today's paints are much softer and easier to chip. My last car (2007 Lexus ES 350) was great - except for how easily it chipped. I had the front bumper and hood repainted after 3 years and it could have used it again.
On my new Pathfinder the day after I bought it I had clear vinyl (clearbra) installed - entire front bumper, hood, both front fenders and both side mirrors. The vinyl is cut to the edges of each surface so you don't know it's there. I also have it on my Z, although that is a 1/2 hood, front corners of the fenders and mirrors job. You do see the line across the center of the hood where the vinyl ends. The shop that did mine routinely does high end cars - Porsches, Corvettes, Jaguars, Mercedes, etc. The full Pathfinder job was $1350.00. The smaller 370Z job was $350. So far not a single ding. If it protects from dings for 3 years it will have been cheaper than a paint job, plus endless hours trying to do touch-up work. Yes, I'm that anal. Of course, something big enough to dent the metal will still do that, but I should avoid the chips.
Undercoating would be the most effective especially if you live in an area where they use salt to deal with the snow. there is a huge issue with bolts underneath vehicles to seize up and rust from the salt. So the underbody coating and protection can help with that issue.
So undercoating is no longer rust proof? When buying a brand new vehicle I would want to paint protect and rust proof to retain the manufacturer quality for as long as possible. I guess it would kind of depend on the buyer and how anal they are about keeping their car in pristine condition.