You would be hard pressed to find even a moderately priced tent without sealed seams. Even most factories in China factory seam seal tents. As others have pointed out, a four season tent will have ventilation issues. As far as make / brand, you will not gain anything with a tent from brands such as TNF. Most moderate to high quality tents are coming out of a hand-full of factories in Korea. Those same factories / production lines crank TNF one day, Big Agnus the next, and REI and Hardwear next week. Inevitably, due to margin structures, you are going to get more bang for your buck with REI. REI has the best designers in the market and the strictest testing protocols. Their REI Outlet is a great place to look, as is the resale center in Seattle. Or just shop someplace like STP for a deal on a brand name tent. As far as bags, the same company owns Kelty, Slumberjack & SD. Sourcing is out of one office and factories are being consolidated. Any low temp rated synthetic bag will work fine. Use foam or a self inflating mattress on your cot, as others stated. If you want to break the bank on an exceptional bag get a Montbell. Note that Marmot Mountain Works stores have little to do with the company Marmot. They are separate entities and have been for years. The same dude who owns the store in Bellevue owns Backpacker Supply in Tacoma.