You are absolutely correct on both points. ANd there are many more
versus to prove it.
Pertaining to slavery however, God does not command there to be
slavery. He only gives instructions on how best to treat them if you
do own slaves. Currently the world has banned slavery. I would not
want to be a slave, so I am glad it is banned. Kind of hypocritical
for the Free World to enslave people (which it has but called by
another name, thats another topic).
Pertaining to mixed marriages there are many versus that specifically
speaks on this. I dont have the time. In summary God wanted his
people to be a Separate Holy People. But, his people disobeyed and
scripture and history tells what happened to them. After Exodus when
God freed the Hebrews from Egyptian slavery he allowed them to go into
slavery by the Babylonians (Ezra, Nehemia) for disobeying, and then
the Diaspora scattered them for disobediance.