The Missing Pillow : Mark 4:35-41 cum parallelis

Several details in Mark´s narrative of Jesus stilling the storm have disappeared when we turn to Matthew´s and Luke´s telling of the same story.
1.The pillow in the stern on which Jesus rested his head when he fell asleep has been omitted
by Mt and Lk.
2.”The other boats” which followed the boat where Jesus and his disciples were voyaging are
not mentioned by Mt and Lk.
3.The observation that Jesus embarked ”just as he was” (whatever that can mean) is missing in
Mt and Lk.
4.In Mark Jesus regards the storm as a hostile adversary to whom he addresses himself in direct
speech (”Be silent and keep your mouth shut”). Mt and Lk only report indirectly what Jesus
does (”he gives order to…”).
My question is now why Mt and Lk neglected and left out these colourful facts
(colourful at least to our modern eyes) from their narratives and what can be
deduced from the fact that Mark “remembered” them.