  Cepheids in multiple systems provide information on the outcome of the
formation of massive stars. They can also lead to exotic end-stage objects.
This study concludes our survey of 70 galactic Cepheids using the {\it Hubble
Space Telescope\} (\HST) Wide Field Camera~3 (WFC3) with images at two
wavelengths to identify companions closer than $5\arcsec$. In the entire WFC3
survey we identify 16 probable companions for 13 Cepheids. The seven Cepheids
having resolved candidate companions within $2"$ all have the surprising
property of themselves being spectroscopic binaries (as compared with a 29\%
incidence of spectroscopic binaries in the general Cepheid population). That is
a strong suggestion that an inner binary is linked to the scenario of a third
companion within a few hundred~AU\null. This characteristic is continued for
more widely separated companions. Under a model where the outer companion is
formed first, it is unlikely that it can anticipate a subsequent inner binary.
Rather it is more likely that a triple system has undergone dynamical
interaction, resulting in one star moving outward to its current location. {\it
Chandra\} and {\it Gaia\} data as well as radial velocities and \HSTSTIS and
{\it IUE\} spectra are used to derive properties of the components of the
Cepheid systems.
  The colors of the companion candidates show a change in distribution at
approximately 2000~AU separations, from a range including both hot and cool
colors for closer companions, to only low-mass companions for wider
separations.
