Sisters of Mercy -- "Give a treasure" is still not clearly defined. Does the player to your left get the treasure in their hand, or in their discard, or somewhere else? This action probably warrants an Attack type, though it is strange that it only affects the player to your left.
Ale House -- You need to add either "or reveal a hand with no Treasure" or "If you do" to the first line.
Confessor -- This card doesn't work. A Treasure with +2 Actions will only be useful in conjunction with Black Market; +Actions are otherwise meaningless because you don't play Treasure until after the Action phase is done. Also, the "while this is in play" effect does not really make sense as such -- that ability is much more of a "when you play this" effect. It is oddly specific, and generalizing it would make the card too powerful for $2.
Crusader -- The wording here is not consistent with other Dominion cards. It should start with "Choose one:" intead.
Helping Hand -- Not sure. Gut says it is too powerful, but the ability is probably not much easier to trigger than Tunnel.
Infirmary -- For better wording, refer to Steward for an example of a choice giver, Horse Traders for the reaction mechanics, and Graverobber for the trash gaining. It should go something like:
Infirmary
$3 Action-Reaction
Choose one: +2 Cards; or trash up to 2 cards from your hand.
---
When another player plays an Attack card, you may set this aside from your hand. If you do, then at the start of your next turn, gain a card from the trash costing up to $5 and discard this.
The choices are decent. It is like Steward, trading the +$2 option for slightly better trashing (you are able to trash just one) and a reaction.
The reaction will be very situational. Unlike Graverobber or Rogue, Infirmary does not do anything to ensure that there are some desirable cards in the trash. Also, many games you will not want to use the reaction at all because you would be forced to gain something bad from the trash. Not to mention it will often be better to save the card to play it instead of discarding it for the reaction.
Lady of Learning -- +1 Action should be at the top of the card; there's no reason for it to come after. I'm not terribly fond of the assymetry of having only you pass a card to only the player to your left. It seems much like an Attack.
Patron of Arts -- detailed comments were given in the thread you posted for this card, and it looks like you took my wording suggestion. This still needs a "While this is in play" clause.
Pied Piper -- blind discard from the top of the deck is not an attack. Consider Tribute.
Sculptor -- I think this is a $5 effect. Drawing the best 2 of 4 cards is already pretty good; +$2 on top of that is very strong.
Shepherd -- This is a common idea. I personally don't like it much, but for no particular reason. It's probably fine.
Sisters of Charity -- I don't know. Forcing you to discard a treasure certainly makes it weaker than a regular Village, but then there is the possibility of some Silver gaining. Granted, that just makes it more likely that you'll have to discard a treasure the next time.
Cudgel -- +2 Cards, +$2 is already quite strong, though it is hard to evaluate. The attack is pretty weak though. The discard option will probably be chosen often, especially since it has the "victim" draw a card to start. Curse gaining might come into effect if Cudgels are chained (similar to Torturer).
Savoyard -- As I read it, it seems to grow exponentially. 1 Savoyard is worth $1, but 2 are worth $4, and 3 are worth $9. But note that 2 Fool's Gold are worth $5 and 3 FG are still worth $9. Savoyard only surpasses FG when you have 4 of them, despite costing more and lacking a reaction!
Furthermore, I am not sure if the phrasing works as intended. First, the usual phrasing is "While this is in play". More to the point, Treasure usually grants the player coin on play. You are using [a version of] "while this is in play", which are sort of "passive" effects on cards. But the coin generation from playing Treasure is more of an active effect.
Inventor -- Again, the stock phrase is "If you do..."
Fundamental problems of this card have alrady been posted in the thread you made for Inventor. How do you return a card if it has been shuffled into your deck (which is a possibility)? The play restriction also conflicts with cards like Golem and Throne Room.
For the latter problem, look to Crossroads for a fix -- have it do the desired actions only the first time you play it, but nothing major otherwise. Then you can play a second or third Inventor. It just wouldn't be useful.
That said, I don't think there is a good way to make a card that temporarily gains cards from the supply. Band of Misfits is the working version of this concept.
