No.
You are considered a Jew if your mother was a Jew. You are a Catholic if you were baptised in a Catholic Church. So it is entirely possibly to be a Jew who is a Catholic.
Einstein was a non-theistic Jew, so he did not baptize any of his children.
There is no specific ceremony for a Protestant converting to Catholicism, but anyone entering Catholicism must be Baptised.
Yes, by giving up the religion, or simply converting to different religion. Jews during the Third Reich in Germany could convert, but as soon as a Jewish ancestor was found in your bloodline, you were considered a Jew. In other words, converting to another religion did not help them. Most 'Jew-spotters' seem to regard anyone with a Jewish grandparents as a Jew. To put the matter differently, it depends on the definitions used.
No. He was with it always! He is God!
No the person would have to be still living. If someone has died without being baptised a 'Prayer for the dead' can be said and offered up.
Yes, it is possible to marry a Catholic without converting to their religion.
The wandering jew plant benefits from exposure to sunlight by using it to photosynthesize, which is the process of converting sunlight into energy to help the plant grow and thrive.
this is debatable some say to be a Sikh all you have to do is be born as one some say to be a Sikh you should believe in the faith some say that to be a Sikh you must be practising others say that you must be baptised, or at least be planniing to be baptised at some point in your life if you wish to consider yourself a Sikh
Yes, anyone can attend, baptised or not baptised.
No Peter was not water baptised.