If it is between the 2 choices you shortlisted, I will go for the first one from Decathlon. Then, it is only 6 speed, meaning it is neither here nor there when you are riding as the rear gears (that's the only gear) starts at a high-ish gear and stops at the low-ish gear. Not even good for flat roads and even worse for uphills.    You can't compare 6 geared bikes of 20 inch wheels with 6 geared bikes of the regular 26 inch bikes. So, don't get me wrong, OK 

As for the second choice, the Y-framed bikes are SOOO...........OUT already. That spring coil in there don't work!  So, I would say, you got both choices wrong. I am also very sure, these bikes won't last. Ride a few months and it will end up squeaky and straddling on. Spend a little more and hunt for a proper folding bike. Even this used one will do better than the one you picked, even if they are 70 percent  condition! 

http://bicyclebuysell.com/item/366443/dahon-eco-c7
http://bicyclebuysell.com/item/365343/dopp...ch-folding-bike
http://bicyclebuysell.com/item/362204/rale...dable-bike-2015

Or head down to Kimbell Jaya in Cheras and ask Jimmy for for an Oscar Imagine.  Although I never really recommend , they are better now , especially the alloy ones, the steel ones are cheaper. It's almost the same price as the ones you short listed. The Decathon one you choose needs someone to assemble and how much do you think the bike shop will charge. One thing for sure, if you get the first bike that gives problem and uncomfortable to ride, I am sure you will give up riding but on the other hand, if you enjoyed riding it , you will continue to ride on and on and on and eventually upgrade to even better ones, even a B later on.

Why do you think so many spends 7K    just for a folding bike, because they enjoyed it.

Grab it doubly quick ! 

At that price, it really doesn't matter. Usually the gear is only out of alignment which can be rectify easily. Just take a ride and go through the gears one by one. If there's no click clacking sound from the rear when the gears are changed , then OK. Check the fold very carefully and make sure there's no free play. Other than that , it is a matter of appearance.