ID danish chairs  

The one from picture 1 & 2 looks heavily influenced by Hvidt for Soborg but they are not.
From what I saw on google, it seems they are american, made by Lane. But I am probably wrong as I know nothing about american furniture...

Well, you know a little. The first is indeed Lane, part of their Perception line designed by Warren Church (model #305-70). Stained oak. Obviously heavily influenced by both Hvidt and Ostergaard.
There are a few Danish designs with the backrest of the second chair. However, I have not seen one with that raised side rail / hand hold design.
Edit: I should clarify that I think the model number changed during the production of this chair. I had one that was marked 305-70, but there is also an old catalog that has it as model 222-70.

That cross bar with a number on it is stained elm. Lane lined to use elm.

I don't think it's Lane... I solved this puzzle a week or two ago, hang on...

Kurt Østervig for KP Møbler.

I mean I could be wrong. But... did Lane use Rosewood?

Although if that's the number there on a Rosewood chair, I guess? What do I know. Nothing.

I was going to start a thread along the lines of, like, 'American Manufactured Designs That Are Direct Copies', or whatever. And these KP Møbler chairs struck me, because they are so similar. And designs by Stanley, etc.

The arms on the captain's chairs are different than the Lane examples...

mgee76, thank you for educating me to a chair of which I was previously unaware. I always thought the Lane design was just heavily influenced by Hvidt and Ostergaard, rather than being a complete knockoff of an Ostervig design. This link includes a mark with both Ostervig and KP Mobler:
http://bluescape.co/kurt-oslashstervig-for-kp-moslashbler-dining-chairs....
The quickest tell between the two chairs (besides wood type ID, which I continually demonstrate is not in my wheelhouse), is that the Lane design has protruding plugs for the screw-attached backrest, while the Ostervig design does not have any plugs here. The lip bend on the Ostervig also appears to be much cleaner than the clumsy Lane joint, but that may not be so apparent in photos.
Lane photos attached.

Thank you all so much for sharing the knowledge! 🙂
Puzzle solved regarding the Ostervig ones... One of these days I should also start a thread regarding "Portuguese mid century designs that are authentic knock offs of Scandinavian ones".
As for the curved backrests ones they are so familiar in danish designs but yes, the "hand rail" is the mystery here..