Yes, marrying a U.S. Citizen in order to become a U.S. citizen is illegal.
Yes. If the illegal immigrant marries a citizen, they can become a citizen from that.
Children can be citizens on their own. For example- illegal alien gives birth in the U.S., the illegal mother is still illegal but the child would be a U.S. citizen.
Unfortunately, an illegal alien can not become an US citizen if they have been deported before. If they have a felony, they can't become a US citizen either.
if they are not born in canada or if there parents are not citizen
if they are not born in Canada or if there parents are not citizen
No
it is illegal
Yes.
no
No. A baby born in the USA is automatically a citizen, but the mother is still illegal.
The fact that their parents are naturalized really doesn't affect their status. They need to meet the requirements of anyone that comes in and wants to become a legal immigrant. Contact an immigration lawyer for the options that are available for you.