QI used the SP Oshi skill "Vroom, Bari Bari Bari Bari" of hBP04-004〈Yukihana Lamy〉 on a hBP04-047〈Yukihana Lamy〉with hBP04-106〈Yukimin〉attached, and the collab effect "fleur" after that to deal 120 damage to my opponent's holomem.
If I bloomed to hBP04-048〈Yukihana Lamy〉and used Arts "May Today Be a Blessed Day" during the performance phase, does the ability from Arts get +100?

AYes, it does.

QI used hBP04-004〈Yukihana Lamy〉's SP Oshi skill "Vroom, Bari Bari Bari Bari" and chose hBP04-047〈Yukihana Lamy〉.
If I bloom it to hBP04-048〈Yukihana Lamy〉after that, what happens to the SP Oshi skill "Vroom, Bari Bari Bari Bari"?

AThe ability will be carried over even after blooming.

QFor the Arts "May Today Be a Blessed Day" of hBP04-048〈Yukihana Lamy〉, can I choose a back position〈Yukihana Lamy〉with hBP04-102〈Yamena〉attached for its ability?

AYes, you can.
However, no damage will be dealt due to hBP04-102〈Yamena〉's ability.

QI used hBP04-004〈Yukihana Lamy〉's SP Oshi skill "Vroom, Bari Bari Bari Bari" and chose hBP04-048〈Yukihana Lamy〉.
Then, I used Arts "May Today Be a Blessed Day" and downed my opponent's center holomem and back holomem.
In this case, can I draw 4 cards as I have downed 2 holomem?

AYes, you can.