As for the volume pot you may want to explore for an old radio/TV parts shop that may have carried the old Clarostat line. Such product came in bits that could be assembled to make multi-section pots of all types.
As for the 'lytic your best bet is to install a terminal strip underneath and use individual capacitors of appropriate value to subsitute. Be sure to exclude the old lytic--even if it is left in place, and be sure the negatives of the new caps return to the exact same ground point.
Good luck!
