Baptism is adoption into the the Family of God and the Church, and results in the remission of all personal sins and original sin, and the gift of the Holy Spirit. It is the beginning of a new life.
I would refer you to the following, and specific to your question, go to the section "Effects of Baptism"
a person gets baptised
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 im pretty sure they can because i can be an anglican adn change my religion when i get baptised. So the answer is yes
Yes, anyone can attend, baptised or not baptised.
start going to a catholic church if your devoted get baptised and abandoned your old religion
No Peter was not water baptised.
I think Ameyeouse baptised saul
no recording of him being baptised
He was baptised in the church in Stratford.
he was baptised the morning after he was born.
No. To have someone baptised does not require you to be a member of the church at all.
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