  The effect of stellar multiplicity on planetary architecture and orbital
dynamics provides an important context for exoplanet demographics. We present a
volume-limited catalog up to 300 pc of 66 stars hosting planets and planet
candidates from Kepler, K2 and TESS with significant Hipparcos-Gaia proper
motion anomalies, which indicate the presence of companions. We assess the
reliability of each transiting planet candidate using ground-based follow-up
observations, and find that the TESS Objects of Interest (TOIs) with
significant proper motion anomalies show nearly four times more false positives
due to Eclipsing Binaries compared to TOIs with marginal proper motion
anomalies. In addition, we find tentative evidence that orbital periods of
planets orbiting TOIs with significant proper motion anomalies are shorter than
those orbiting TOIs without significant proper motion anomalies, consistent
with the scenario that stellar companions can truncate planet-forming disks.
Furthermore, TOIs with significant proper motion anomalies exhibit lower Gaia
differential velocities in comparison to field stars with significant proper
motion anomalies, suggesting that planets are more likely to form in binary
systems with low-mass substellar companions or stellar companions at wider
separation. Finally, we characterize the three-dimensional architecture of LTT
1445 ABC using radial velocities, absolute astrometry from Gaia and Hipparcos,
and relative astrometry from imaging. Our analysis reveals that LTT 1445 is a
nearly flat system, with a mutual inclination of 2.88 deg between the orbit of
BC around A and that of C around B. The coplanarity may explain why multiple
planets around LTT 1445 A survive in the dynamically hostile environment of
this system.
