1. Looks like vinyl to me but you can tell for sure by examining it with a magnifying lens. Real leather has pores. Fake leather has shallow little indentations meant to resemble pores. You can slo look for a cut edge somewhere under the chair. Most vinyl has a backing fabric, usually a knit.
2. It has a tinted clear finish to make it look look like some other species of wood, usually one that is of more value than what the real wood is. This was done a lot on American furniture. (still is.) You can safely strip it, if by safely you mean without damaging the wood itself. First you should determine what the finish is, though---lacquer, varnish, or something else. Most likely it's lacquer or varnish.
3. Hard to say what wood is is though the grain on that one closeup looks like oak, sorta. Could be maple? I dunno.
4. It's a nice enough vintage American armchair. Not of great value but if you're just starting out in this style and don't have much money to spend--sure, why not. You can always trade up as your means permit.
5. Late 50s to mid 60s
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