Q1: Can I use this card's digivolution requirement to digivolve for a cost of 5 even when my Takuya Kanbara has more than 5 Hybrid trait cards under it?

Yes, it can digivolve.

Q2: If this card gains Piercing from another card's effect, then this card attacks and deletes an opponent's Digimon in battle, do I perform the security check for Piercing after this card's Your Turn effect activates?

Yes. After this card's Your Turn effect activates, then you perform the security check for Piercing. This card's Your Turn effect and Piercing trigger simultaneously, but the activated Piercing is processed immediately before the attack ends, therefore Security Attack +1 is first gained from this card's Your Turn effect, then you perform the security check for Piercing.

Q3: BT18-088 Takuya Kanbara & Koji Minamoto digivolved into this card, and the memory gauge moved to 1 on my opponent's side. Then, I used this card’s When Digivolving effect to attack and used this card's Your Turn effect to unsuspend it. Can I then use the End of Your Turn inherited effect on BT18-088 Takuya Kanbara & Koji Minamoto in this card's digivolution cards to attack a player?

Yes, it can attack. When digivolving into this card, the turn end conditions won't be met until all of the resulting processing has been resolved. In this case, this card's When Digivolving effect, Your Turn effect, and any effects triggered by them must first be resolved, and then the turn end conditions will be met. Then, the end of the turn timing will occur and BT18-088 Takuya Kanbara & Koji Minamoto's End of Your Turn effect will trigger.

Q4: Can this card's digivolution requirements also be from "Takuya Kanbara" with more than 5 cards with "Hybrid Body" in the trait below, at a digivolution cost of 5?

Yes, it can digivolve.

Q5: When an opponent's Digimon is deleted in a battle in which this card, which has gained "Penetrate" by the effect of another card, attacks, does this card's Your Turn effect activate and then check with "Penetrate"?

Yes, it activates. and then checks with "Penetrate". This card's Your Turn effect and "Penetration" are triggered at the same time, but the activated "Penetration" is processed just before the End of Attack, so the "Penetration" is checked after the "S Attack +1" is obtained by this card's Your Turn effect.

Q6: The situation is that you evolved from "BT18-088 Takuya Kanbara & Koji Minamoto" to this card, and its memory is more than 1 on the opponent's side. At this time, I attacked with this card's When Digivolving effect and became active with this card's Your Turn effect. After that, can I attack a player with the When Digivolving effect of End of Your Turn of this card's BT18-088 Takuya Kanbara & Koji Minamoto, which is the digivolving card?

Yes, you can attack. Until you digivolve to this card and resolve all the processes caused by it, you still do not meet the end-of-turn requirements. In this situation, all When Digivolving and End of Your Turn effects of this card and the effects caused by them are resolved, and the End of Turn condition is satisfied. After that, it becomes End of Turn, and the End of Your Turn effect of "BT18-088 Takuya Kanbara & Koji Minamoto" is triggered.

Q7: Does this card's When Digivolving effect, if this card has three colors of digivolved cards, choose and trash three of the opponent's digivolved Digimon and choose and rest three of the opponent's Digimon?

Yes, for each color of the digivolution source of this card, choose and trash one of your opponent's Digimon digivolution sources and rest one of your opponent's Digimon.