Q1: When I would play a Digimon card with the ADVENTURE trait from my hand, if I activate the Your Turn effects on both this card and [[ST20-12|ST20-12 Sora Takenouchi & Kari Kamiya]], is the play cost reduced by a total of 2?
Yes, the play cost will be reduced by a total of 2.
Tai Kamiya & Izzy Izumi ST20-13 R ADVENTURE [Your Turn] When any Digimon cards with the [ADVENTURE] trait would be played from your hand, by suspending this Tamer, reduce the play cost by 1. [Opponent's Turn] All of your Digimon with the [ADVENTURE] trait gain <Blocker>. (This Digimon can block in the blocker timing.) --- [Security] Play this card without paying the cost.
Tai Kamiya & Izzy Izumi ST20-13 R ADVENTURE [Your Turn] When any Digimon cards with the [ADVENTURE] trait would be played from your hand, by suspending this Tamer, reduce the play cost by 1. [Opponent's Turn] All of your Digimon with the [ADVENTURE] trait gain <Blocker>. (This Digimon can block in the blocker timing.) --- [Security] Play this card without paying the cost.
Tai Kamiya & Izzy Izumi ST20-13 R ADVENTURE [Your Turn] When any Digimon cards with the [ADVENTURE] trait would be played from your hand, by suspending this Tamer, reduce the play cost by 1. [Opponent's Turn] All of your Digimon with the [ADVENTURE] trait gain <Blocker>. ---