Welcome! I'll take a shot.
- You can create multiple collections, so you could have a separate collection for your gold cup rookies.
- I don't think so; at any given time, a member is either open to all trades, or closed to all trades. Probably best to simply not put your needs on your want list until you're ready to trade for them.
- The prices/values attached to each card are mostly unreliable, and more to the point, some (many?) members loathe them and specifically ask that they are not used to balance trades. I figured they were probably unreliable and speculative, and they have gotten a bit better with the inclusion of SportsLots prices, but it took some time to realize just how unpopular they are.