Q: How to change the keyboard?
A: There is no need to change anything to your VM parameters in order to change the keyboard layout. You only need to configure correctly the keyboard layout inside the VM operating system. This is done depending on the OS you are running inside your VM.
Indeed QEMU defined a VNC protocol extension for send hardware scancodes from the VNC client. This avoids any kind of translation on the VNC client machine, or in QEMU. Hardware scancodes are sent from VNC client to QEMU, which sends them to the guest. Only the guest needs to do the translation.