Just get along, and be a family until the parents come out. Meanwhile you could save your money up, study something that makes money fast and a lot, and you her could leave the children with the morons you call each other parents. Otherwise they are going to go into foster home and is going to impact them.
It is an odd situation. Like a song. "I met this girl, we hit it off, but then her dead-beat parents went to jail and left us in charge of the runts. Now we are a young couple in charge of children, I really want to make her happy but I do not want to be selfish"
Point being is that man is love so you have to do it for the siblings and do it for her. I could not mind being a surragate dad right now. As long as I was getting poon.