At the risk of becoming entangled in a long, drawn out debate about the theology of marriage with a non-Catholic (an activity for which I don't have the time or patience), I will point out that we've been discussing validity in the context of sacramental marriage.
Keep in mind, in Catholic theology, marriage is a sacrament. Like baptism, or the Eucharist, or Holy Orders.
But not every marriage rises to the level of the sacrament. And that's the point of the discussion. Some marriages may exist civilly, that is, they have the legal status that is granted by the state, but they don't have a sacramental quality.
To your first question, it depends. In many places, the Church requires that those who wish to be married in the Church must generally also have a civilly-recognized marriage, just as, in most places, in order to initiate a case before the marriage tribunal to ascertain the validity of a marriage with an eye toward a declaration of nullity, one must have already been granted a civil divorce.
But those are prudential decisions on how the Church thinks the intersection between the secular and the spiritual work in a given time and place.
The Church recognizes the civil institution, and in many ways, the civil institution is compatible with and complementary to the ecclesiastical institution, but they aren't quite the same.
The distinction comes down to the difference between natural marriage and sacramental marriage.
“So, talking about churches giving their ‘blessings’ is more about feelings than it is about validity. Do you agree?”
No, I don't agree. You're mixing terms. We've been talking about the sacramental nature of marriage between two Christians, not the civil legal nature of civil, marriage, generally.
sitetest
BB (and the rest of you non-Catholics); you ain't worth my time.
But I'll post something; anyway...