I'm referring to the rule which says that after you've started the Hook Mountain Massacre adventure, you can pick up any Base Game cards, as well as those from adventures numbered at least two lower than the current one. (So when playing Hook Mountain Massacre - the third adventure - you can also pick up cards from adventure pack one.)
Now, as you may have already realised, ending up with a lower number of cards than allowed by your deck after a scenario is very simple: you only need to *give* some of your cards to another player during the game. (You only need two or more players.)
So there is nothing keeping you from picking out Ilsoari Gandethus, for example, and giving him to Merisiel, who can always just evade the Sandpoint Devil in case he is summoned.
In fact you can simply pick up all of the good boons from the box, like the Holy Candle for example.
This concerns me regarding Kyra in particular, who will at some point with her role be able to recharge Blessings of Saranrae (or place them on top of her deck) instead of discarding them. Given the method outlined above, there is really nothing stopping you from simply putting all four (or five) of these blessings into Kyra's deck.
I think we are going to house rule this, so that all "given" cards have to be returned to the original owner after the scenario. But there are still plenty of locations in the game which are closed upon banishing a card. So with Kyra in a group the goal should certainly be to banish blessings and replace them with Blessings Of Saranrae after you started the Hook Mountain Massacre.