The plugs you linked to are Irdium IX plugs, which are the same Nissan uses in its Value Line spark plugs. They are a good plug and will work fine, but they usually last around 60,000-70,000 miles...and short of the replacement interval of 105,000 miles. Your original plugs from the factory are Laser Iridiums, NGK # 93759. A less costly option that will still last 105,000 miles is the Laser Platinum NGK # 6240.
There are a number of sources I use for parts. Rockauto.com is a good source online. They carry the NGK plugs plus a large assortment of brake parts, air filters, cabin filters and whatever else you need that's not a factory specific parts. Try to stick with reputable brands and preferably OE parts suppliers to Nissan, like Hitachi, KYB, NTK and NGK, Bando and Aisin. Everyone will have their preferences for oils and filters.
For me and many others, Valvoline Maxlife full-synthetic ATF is great for transmission service, transfer case service and power steering. I get it for $18/gallon jug at Walmart. While there, I also get SuperTech full-synthetic 5W30 for the engine oil, which runs around $17/5-qt. jug. I'll also get diff oil from Walmart, Full-synthetic 75W-90 from either SuperTech or Mobile One.
I usually get my NGK plugs from Advance Auto Parts. I'll purchase them online and pick them up at the store, using an online discount code for 20% off or more. That said, the NGK 93759 isn't always in stock at the one near me. I also got my Airlift 1000 air bags from them, which were ordered online with a discount code and shipped to the house.
I use Pentosin for engine coolant as they make the OE coolant for Nissan. 2011 should be blue coolant, which is Pentosin Pentofrost A3 and is sold as pre-mixed (no adding water). Two gallons should cover a drain and fill. For earlier Pathfinders with green coolant, it's Pentosin Pentofrost A2, which needs to be mixed with a gallon of distilled water (Walmart @ 67 cents).
Air and cabin filters I usually get from Rockauto. Beck-Arnley, Hastings, Wix and Denso are all good brands. ATP and Denso are my usual picks for cabin filters from Rockauto. I also get wiper blades from Rockauto. Last ones I got were Valeo 900-series and they've been great, so far.
As mentioned earlier, Rockauto is a good place for brake parts. Akebono PRO-Act ceramics, Raybestos Element3 Advanced hybrid and Wagner OEX are all good replacement pads. Beck-Arnley uses OE pads which are the same the come from Nissan. An increasingly popular front brake upgrade on V6 Pathfinders is to replace the front brake pads and front brake calipers w/ mounting brackets with those for a V8 Pathfinder; the hoses, master cylinder, steering knuckle, wheel hub and caliper bracket bolts are all the same between the V6 and V8 Pathfinder, so it's a simple, bolt-on swap. The V8 uses a 1" larger diameter rotor.
The fuel filter is part of the fuel pump module in the tank and is not serviced as part of routing maintenance.
For any genuine Nissan parts, I usually shop at NissanPartsDeal.com or CourtesyParts.com. If you have any other questions, just ask!