While the geologic record for Chicxulub is well documented the
commonly known "fact" that this caused the dinosaurs to die out is
debatable since their demise was spread over millions years covering
both pre and post Chicxulub impact; not just over a few weeks or
months, or even a few hundred years..
The seabed record does show Chicxulub caused a drop in temperatures
for some time period and significant species losses.. There have been
a number of other massives die offs seen in the fossil records that
are not well explained and not all can be tied to an impact...

The other issues you point out, such as the genesis of the earth's
moon coming by impact from an extra solar body is the currently
accepted theory of mainstream cosmologists, less a maverick or two...

denny