Yes, you can.

You process this card's [Your Turn] effect first. After processing the "when you would play" effect, you can then perform the DigiXros. Once you use this card's [Your Turn] effect to place cards under the card to be played, then you place the cards for the DigiXros under the cards you just placed for the effect.

No, you can't activate it. This card's [Your Turn] effect triggers when you would play 1 level 4 or higher [Bagra Army] trait Digimon card. It doesn't trigger when you would play 2 or more at the same time.