1) and 2) are both comfortably $4 cards. 3) Is easily a $6.
1 and 2 are exactly as Schneau says, basically better than Smithy for Big Money, and terminal money is often good in many engines. One notable thing about them is that they're less likely to miss reshuffles than Smithy, and less likely to collide, so you can comfortably grab them a little sooner. In addition, note that Action2/Silver has a 5/6 chance of being played without missing the 2nd reshuffle, while Smithy/Silver is a much lower 5/12, AND at that point in the game your average treasure density is <$1, so it also provides slightly more money on average. Same argument holds for Action1.
3 is a card that everyone and their mum has concocted at some point, and the general consensus has always been that it's too good as a $5, and balanced, but boring, at $6. The reason is that it provides two very strong BM type effects - in BM, +2 cards is pretty much just extra money, so this is a terminal providing probably an average of +$4. Note that it's providing probably a better average amount than Adventurer, probably a good +$1 over Harvest and more over Counting House, all $5's. In an engine, it's alright, it manages to be a bit kind of everywhere, giving you a little draw (but you want more) and a little terminal money, so if you have excess actions, it's better than Gold almost certainly.
Donald has in fact addressed all three of these cards before. He considered 1 and 2 to look 'wonky' and not be that exciting, and 3 I believe was playtested at $5, bumped up to $6, and then dropped for being boring.