4) Trepidation from fundamental sects of Christianity and
other religions which >>would be considered contact with
"demons and satanic influences" since some Biblical
authorities teach that Satan is "prince of the air."
Influential religious groups could
ignite a religious war.

You might be on to something here, although I wouldn't worry about a
Jihad myself.  Christianity was finally able to accomodate a round
Earth, and a sun-centered solar system.  I think they would be able to
adjust.

But those other beliefs never were fundamental to the religion itself,
but were outgrowths of Xtianity's dependence upon Aristotelean
philosophy after Thomas.  Alien life raises crucial questions about
the soul, the nature of salvation, and the afterlife that geocentrism
and flat-earth (never really a Xtian idea, btw) never did.

I seem to remember quotes from interviews with both the Pope and Dali Lami
from discusions with Sagan, Clarke or Aimov (forgot which) in which both
were asked basically the same ie what would happen.  Neither considered it
a problem.