Personally, I think you'd be mad to cannibalize that machine because you'll never build one as good. The parts won't transfer very well as they are sized for a machine that size and will be far too large for a smaller machine. If you really don't have space and can't make space then I would clean it up and sell it on then put the money into a smaller machine with more suitable and modern parts.

The spindle could be used with a Single- phase to Three-phase VFD, these can be bought from China for a few £100. The rest of it will be 240V single phase or 110v which is easily enough transformed.