64 megs of "other" memory? Why they are not mapped as fast ram
It is. Fast memory is displayed as other memory.
There would be no way to map 64MB as ranger memory ("slow memory") anyway, maximum is 1.75MB.
And what's the purpose of that voltage module?
Apparently the same board is used for Viper 1240, where 68040 is 5V device. 68060 is 3.3V. So the voltage module adjust the 5V->3.3V.