Name those parts (swivels)

[NotSure]

I don't know about HP swivels, but you do need to be careful to get the right adapter when converting from 3/8" or 7/16". HP adapters can have a very small hole to restrict air flow.
3/8" to 1/2" LP on left 7/16" to 7/16" HP on right.

 

[Chicken SCUBA]

The central post of the swivel that the outer part swivels on has one hole through it for the air to flow through. If it is 90 degrees to the port and the hole lines up with the outer hole to the hose, the flow is adequate. If it does not (because it swiveled when the hose moved) there is a considerable restriction on air flow that has been cited as the cause of accidents in a couple of reports that I have seen, especially when attached to the long hose in an air share situation.

I don't know any more about it than anyone else but I have a LP one that I used for several years on my Mares second stage. FYI the center post has four holes to flow through and a substantial "camber" around those holes.