Danish chairs ID, please.  

Are they...
... worth reupholstering? I am not sure I can save the one on the right.

they
are both very attractive and I think of a high quality. Lemme see what I can find

the left one seem like a Ruster-chair
designed by Yngve Ekstrom.
With matching ottoman?

I was
thinking Ekstrom as well because of the arms

I think...
... you are correct about that. Hard to tell on the other one. Possibly I could have an arm fabricated?

BJ, Thanks! I picked up 2 of these ottomans 3 weeks ago. I decided then that they were likely Swedish, but could not find them anywhere I looked. Very timely.

The one to the left is most likely "Mingo" by Yngve Ekstrom, designed in 1956.

I think you're right. Dropped them off at the upholstery place today. Now, what kind of fabric do I put on these? What would be the most appropriate and authentic? Thanks.

I think Kvadrat Tonus would look very nice on them. Hallingdal would also be nice I think, and appropriate.

What about something like Maharam Melange?

Do you mean Maharam's Melange Tweed?  It's nice but it's very pricey and also has a lower wear rating than the classic Kvadrat wools like Tonus, Hallingdal and maybe Tonica, too.  I have swatches of Melange Tweed and it feels softer and is more loosely woven than any of the above.  I don't quite get why it costs so much more.
Hallingdal is gorgeous but it's scratchy---may be a factor if wool has that effect on you.  I find it itchy through lightweight summer clothes but winter clothes will block it.  Tonus is softer but also only comes in solid colors, so it will not hide lint and stuff so well.
There's also Divina which comes in a line of heathered colors called Melange.  Divina is a wool felt.  I did one chair in a heavy felted wool from Knoll once---it's a little tricky to do corners neatly in it.  I don't know if the Divina felt is more maleable, though.
Have you looked on Modern-Fabrics.com?  They often have Kvadrat/Maharam wools listed and you can also find them on Ebay.  Just check with your upholsterer first to find out how much you need.

Thanks for explaining that. I was already looking on that site and wondered which might work best. I ordered some swatches, but here are the few I'm considering...
http://www.modern-fabrics.com/store/product-info.php?pid1248.html
http://www.modern-fabrics.com/store/product-info.php?pid2579.html
http://www.modern-fabrics.com/store/product-info.php?pid1691.html
http://www.modern-fabrics.com/store/product-info.php?pid3060.html
http://www.modern-fabrics.com/store/product-info.php?pid3245.html
Just sorta waiting for the swatches, but I don't have any experience with these fabrics. What are some pros/cons? The durability and price of the Manner and Medium examples is attractive. I sorta need to feel them, though. Thanks.

Also I wasn't sure whether or not to put buttons on the back. The few I've seen online seem to have a couple buttons, but the upholsterer said this wasn't necessary. Can't make up my mind. It appears that maybe it did have buttons, but they are missing? What do you think?

The Maharam "Medium" and "Manner" are 100% polyester fabrics and not appropriate for your pieces.  They are less expensive because they're cheaper to produce.  They're durable because they are made of petroleum based sythetics.  They're intended more for office furniture.
The Divina Melange is is nice stuff but the Hallingdal will be easier to work with for your upholsterer.  It's just kind of wonderful in all aspects except for being scratchy.  The Divina is pretty soft.
Definitely do buttons.  It's part of the look.  Three across is is fine, just make sure they are at the height of that one remaining one and spaced correctly---luckily you have a side one so you don't have to guess at how far from the edge to put it.