With one exception, any modern (second hand) sewing machine will do everything you want and more. The exception is 'packs'. If you are making silnylon packs, no worries, but if you are trying to sew 2 or 3 layers of 500 denier Cordura, then quite a few modern machines will struggle badly. They are just not designed for that. I use an old black Singer for my packs. Straight stitch only however.
Straight stitching and triple zigzag are usually enough for most things. Single stitch zigzag is available on any modern machine too, but it puckers light fabric badly. Bartacks are just single or triple-stitch zigzags with a very short stitch length.
Control over the tension IS REQUIRED. With silnylon I usually reduce the tension and sew with the fabric slightly stretched, to avoid it all puckering up. This is important. On the other hand, when sewing a couple of heavier layers I have to increase the tension to get a balanced stitch. You will need to experiment at first - stuff sacks!
Zippers and such are handled by having a zipper-foot. If the machine does not come with one, visit your local sewing shop.
Mesh - tricky stuff! It tends to skew under the foot. It can be handled with a bit of practice and the use of MANY fine pins. yeah - go buy 2 packets of the finest dress-making pins they have.
Needles: I use the smallest I can get away with. That is usually about 2 sizes thinner than some 'experts' recommend. They recommend big fat needles ONLy so you don't break them, but the fat needles damage silnylon and other fine fabrics.