1) If you are looking to learn about the vintage cards and sets there is a HUGE WEALTH of information here on the boards and some incredible people - try doing searches in the forums that are applicable to the cards you are looking for. While there are people here who "invest" in cards and others while not investors who make decisions considering potential future pricing, I would say that based on my experience, most here are more focused on just "collecting" - so if you are looking for more pricing based or speculation information this might not be the best place to find it.
2) The list of players you like also happen to be some of the most collected players. I would think the "big names" in the "big sets" are a good starting point - "Big sets" - T206, 1933 Goudey, 1952 Topps - "Big names - T206 Cobbs, 1933 Goudey Ruths, 1952 Topps Mantle, Robinson. Aaron - 1954 (ROokie) or 1955 or 1956.
3) Re: Price spikes - it is widely believed that there was a small group of individuals who manipulated the market creating the price spikes. This hobby because of some of the $$$ involved has been susceptible to those less scrupulous looking for fast $$$. I encourage you to do your homework to understand some of that history as I suspect it is possible to happen again. Do google search for "baseball card market manipulation" and "slabgate" to get your feet wet with some of the less attractive goings on in the hobby. Forewarned is forearmed.
4) I follow many auctions and have seen some incredible prices - not across the board, but too many to assume "outliers" - not sure what the story with that is. Most regular issue (as opposed to regional or test issue) Post war cards have enough supply that I would probably peg a price point I want to be at and be patient. Possibly a bit less so for prewar
A couple of possible helpful resources for you:
Vintage Card Prices (VCP) -
https://vintagecardprices.com/
and
PSA auction prices database (this doesn't capture every sale and is for PSA graded cards only) -
https://www.psacard.com/auctionprices/
Hope that's a helpful start.
Most importantly - enjoy what you collect!
Howard