Actually, the MapIR...-style options are correct, if "MotionSource" "ir" is used. MapA etc. is correct, if "MotionSource" "ir" is not used.
I can successfully operate the Wiimote as a mouse replacement using exactly the same 60-xorg-xwiimote.conf as the OP.
You might not have xf86-input-xwiimote installed?
It's not installey by default. You can fix this by running:
git clone https://github.com/xwiimote/xf86-input-xwiimote.git && cd xf86-input-xwiimote
./autogen.sh
./configure --prefix=/usr
make
make install
The last command must be run as root or using sudo. (Alternatively, create a .deb package with debhelper and install that using dpkg.)
Afterwards you must reboot (or at least restart your X server) for the changes to be effective.
Buttons should work out of the box. For proper motion detection, you need one bright IR source as a reference below or above your screen. (Two IR lights - as used by Nintendo in the original sensor bar - are fine as well.)