Apart from the chestnut, the bay and the second pic of your horse all have poll lower than crest if the neck. We call this "falscher Knick", means wrong fold, I guess it could be translated. No true collection.
The chestnut is most likely collected, though tense.
The first grey and the bay are in "Arbeitshaltung", working frame, but not in full collection. The second grey is a youngster and could definitely benefit from more forward downward before attempting to pull him together.
Your horse(good looking fella), is on his way, in a nice frame, but still should go forward a lot, not so much being held in that position. Danger of getting the "falscher Knick".
Again, I am old school, by no means a dressage judge, wouldn't want to be one and maybe have a different understanding of true collection.
AND im pretty sure you will post the complete pictures of above horses