Here are my suggested wording changes for the contest-winning cards. I tried not to alter their effects in any way.
Tea House
$4 - Victory
2 VP
--
At the start of Clean-up on the turn you buy this, you may choose a card you have in play. If you discard it from play this turn, put it on your deck.
Tea House
$4 - Victory
2 VP
--
When you buy this, you may choose a card you have in play. If you discard that card from play this turn, put it on top of your deck.
The difference between choosing a card immediately upon buying it and at the beginning of cleanup is negligible. You can't play any more Actions or Treasures at that point anyway.
Canal
$6* - Victory
When the game ends, if the Province or Colony supply pile is empty (if it was available), then this is worth 4 VP. Otherwise, this is worth 2 VP.
--
During your Buy phase, if two supply piles are empty, then this costs $3.
Canal
$6* - Victory
If the Province or Colony supply pile is empty, then this is worth 4 VP. Otherwise, this is worth 2 VP.
--
During your Buy phase, if two supply piles are empty, then this costs $3 less (but not less than $0).
You don't need to specify 'when the game ends'. All VP calculations are done at the end of the game. Also, there are potential rules conflicts when setting a card's cost dynamically. This card says it now costs $3, but this other card says it costs $1 less? How much does it cost? $5? $3? $2?
Pawn Shop
$3 - Action
Choose one: trash a card from your hand, gaining a number of Coppers equal to its cost in coins, putting them into your hand; or trash any number of Coppers from your hand, gaining a card with cost exactly equal to the number of Coppers you trashed.
Pawn Shop
$3 - Action
Choose one: trash a card from your hand, gaining a number of Coppers equal to its cost in coins and putting them into your hand; or trash any number of Coppers from your hand, gaining a card costing exactly $1 per Copper you trashed.
Slightly cleaned-up wording regarding the cost of gained cards.
Crystal Ball
$5 - Treasure-Reaction
Worth $2
When you play this, reveal the top card of your deck and either discard it or put it back.
--
When you discard this other than from play, you may reveal it and set it aside. At the start of your next Buy phase, play this card.
Crystal Ball
$5 - Treasure-Reaction
Worth $2
When you play this, reveal the top card of your deck. Discard it or put it back.
--
When you discard this other than from play, you may set it aside. At the start of your next Buy phase, play this card.
You don't need to reveal a card before setting it aside. Set aside cards are implicitly revealed.
Academy
$4 - Action
+2 Cards
+1 Action
Each other player draws a card, then discards a card from hand.
Academy
$4 - Action
+2 Cards
+1 Action
Each other player draws a card. Each other player discards a card.
You don't need to specify that a card is discarded "from hand" any more than you need to specify that you gain a card "to your discard pile". It's the default.