Q1: How does this card’s Your Turn effect work, exactly?
The effect allows this card to be treated as both white (its original color), and as the colors of its digivolution cards. For example, if a red card and green card are in this card’s digivolution cards, this card is treated as a 3-color white/red/green card.
Lv.5 Kimeramon BT8-084 SR Ultimate | Data | Composite [When Digivolving] You may place 1 level 5 or lower Digimon card from your trash under this Digimon as its bottom digivolution card. Then, up to 4 of your opponent's Digimon get -1000 DP for each of this Digimon's colors until the end of your opponent's next turn.[Your Turn] This Digimon is treated as also having the colors of its digivolution cards. While this Digimon has 4 or more colors, it gets +4000 DP.
Lv.5 Kimeramon BT8-084 SR Ultimate | Data | Composite <DNA Digivolution: 0 from Lv.4+Lv.4>[When Digivolving] You may place 1 level 5 or lower Digimon card from your trash under this Digimon as its bottom digivolution card. Then, up to 4 of your opponent's Digimon get -1000 DP for each of this Digimon's colors until the end of your opponent's next turn.[Your Turn] This Digimon is treated as also having the colors of its digivolution cards. While this Digimon has 4 or more colors, it gets +4000 DP.
Lv.5 Kimeramon BT8-084 SR ultimate | Data | Composite [DNA Digivolve] Lv.4 + Lv.4: Cost 0 [When Digivolving] You may place 1 level 5 or lower Digimon card from your trash under this Digimon as its bottom digivolution card. Then, up to 4 of your opponent's Digimon get -1000 DP for each of this Digimon's color until the end of your opponent's next turn. [Your Turn] This Digimon is treated as also having the color of its digivolution cards. While this Digimon has 4 or more color, it gets +4000 DP.
Lv.5 キメラモン BT8-084 SR 完全体 | データ種 | 合成型 【進化時】自分のトラッシュから、Lv.5以下のデジモンカード1枚をこのデジモンの進化元の1番下に置ける。その後、次の相手のターン終了時まで、相手のデジモン4体までを、このデジモンの色1色ごとにDP-1000。 【自分のターン】このデジモンの色はこのデジモンの進化元のカードの色としても扱う。このデジモンが4色以上の間、このデジモンをDP+4000。