No, the lease you make for QonQer is not registered with the BKR. However, you are of course obliged to report your lease and other loan agreements when you take out a mortgage, for example, if you are asked to do so.
Yes you can, just not free of charge. You return the QonQer and then pay 60% of the outstanding terms. If the lease lasts 3 months, for example, that is 3 x € 62 x 60%, which amounts to € 111,60.