Are there coordinates for where orbiters deorbited? Options

[Antdoghalo]

Are their sources providing tentative coordinates for where orbiters like Venera, Pioneer Venus, Venus Express, or Magellan may have entered the atmosphere much like those for the Pioneer Venus Multiprobe bus at 37.9°S 290.9°E? (Magellan maybe impossible due to it being a farside deorbit)

[Gerald]

I'm not sure, whether this will answer your question in the way you expect, but there are provided trajectory data in the SPICE kernel directories accessible via the anonymous FTP server naif.jpl.nasa.gov.
There are also reduced orbital data, for instance for Magellan in /pub/naif/MGN/misc/dnunes:
 mgn_nav.orb.txt ( 2.45MB ) Number of downloads: 1207

For more detail, you'll need to evaluate the SPICE kernel SPK files.
According to /pub/naif/MGN/kernels/spk/nav/aareadme.txt,
/pub/naif/MGN/kernels/spk/nav/CYCLE6.BSP is ending at 1994 OCT 14 01:01:01.182.
Once you get significant atmospheric drag, further useful trajectory extrapolations through the atmosphere are probably not possible, since the integration of the applicable differential equations would diverge exponentially depending on spacecraft attitude and atmosphere detail. You would get very elongated ellipses, similar to the statistical outcome of stone skimming.