How to edit build.prop without root and without custom recovery?
Is it possible to have build.prop edited in these circumstances?


Unfortunately, no. Build.prop rests in the system partition and that partition is mounted as read-only by the Android. To edit the file, the partition has to be mounted in read-write mode, which requires root privileges which you are sure you cannot gain on this device. 

That said, some of the properties can be altered using setprop tool through adb. Mostly the ones starting with the prefix persist can be changed successfully and the effect be observed in real time. While read-only properties may show successful result after their value altered using setprop, the effects would not be seen.