Forum:Trishula and flamvell firedog, all happen at the same time?

If i activate trishula's removal effect, does this effect all happen at the same time? Meaning i pick 3 targets right away and then they all resolve at the time?

If not is it possible for me to choose an opponent's dandylion first, then choose dandylion again, then a card? Most likely not.

Now for flamvell firedog. It's special summon effect, let's say i have dragunity equipped with aklys and my opponent's dog attacks my equipped monster. I use aklys' effect to destroy firedog. Does my opponent still get to special summon?