The initials sometimes given after a saint's name indicate the religious order, if any, of the saint - O.P. - Order of Preachers (Dominicans), O.S.B. - Benedictines, O.S.F. - Franciscans, etc.
The Catholic Church lists no canonized saint by the name of Amber.
It doesn't have to be but it is tradition to name a Catholic Church after a saint, because of the good things Saints have done, and this means the Church's name reflects the good which the saint did in their life.
Which Saint Catherine Church? There are churches all over the world with that name.
There is no specific Saint Lynn recognized by the Catholic Church. "Lynn" is a common given name, but there is no known saint by that name in the official list of Catholic saints.
The Church is called Saint Peters Basillica.
Saint Francis of Assisi.
You choose a saint's name when you are baptized, and you may choose another saint's name when you are confirmed.
Saint paul
There are many saints recognized in the Catholic Church. However, as of 2014 there is not a saint with the name Hali.
It's the Church of Saint George. See attached link.
Saint George
Saint Peter's Basilica.