in Estonia your rotors will likely be rusted by the time the pads wear out, that has been my limited experience there anyway.
if your calipers are the same as the US Leaf, then i would just use some ceramic pads, and if the rotors are decent then keep them as is, but if they are original they might be shot from the environment anyway.
post a pic of your caliper and rotor diameter. i can measure mine to compare. Rockauto seems to only list one size/shape/mfgr date of rear pad for the Leaf.
i am really surprised that you have managed to wear through the pads though, i am at 85k km (52k miles) with my 2013 and i'm not even half way worn through. Might be the brake pad material difference in US vs UK built Leaf though.
2013 Leaf SL Premium
27k, 93% SoH 2/17 32k, 96% SoH 6/17
46k, 94% SoH 2/18 52k, 88% SoH 6/18