Rear racks on a small wheel bike need to be as tall as on 700c bikes, otherwise your panniers are too low and could be a problem with ground clearance or possibly the drive train. I found that if I used my Carradry rear panniers on my folding bike, the pannier was too close to the shifting mechanism on my Sram Dual Drive for comfort.

But, you should be able to buy and fit just about any rack to a folding bike. That said, a rear rack that pushes the panniers further back may be needed because folding bikes usually have shorter chainstays.

If you needed a rack that was really portable when off of the bike, the Racktime Foldit Adjustable is held together with a lot of nuts and bolts. I am not sure how stiff it is when loaded up with heavy panniers, that could be a weak spot. And if you buy a Racktime or Tubus rack for the rear and need longer stays to attach to the front of the rack to the chainstays or other mounting point on the bike, they make longer stays as options.

I was thinking of taking my folder on an tour on Amtrak, bought the Racktime Foldit Adjustable rack for it, photo below, this bike has 24 inch wheels, I used the optional extra long stays for the rack:



The trip did not happen, so I can't tell you how it worked out.

I do not know how many times I have started reading a thread where someone wants to buy a folding bike, but late in the post they say they want to spend about half as much as they would expect to spend on a full size bike.

If you want to buy a used Dahon for $600 for a trip that otherwise will cost you many thousands, maybe it will work out ok.