Even if they couldn't go to the police etc etc , Lyle , who is 2 years and 10 months older than Erik, could have saved money by renting out the luxury apartment and living in a small one , selling some of the stuff his dad brought him and just stashing away money in general. Also, earn as many college credits as possible.

The moment Erik turned 18 they could have left the family with all the he cash stashed away, and the college credits he earned , which will definitely transfer to any college of his choice. Then just graduate, start making money , legally change their name etc etc They can actually try leaving earlier. No police department is going to waste the resources to go after a 17 year old who left home to go out of state and bring them home

Even if I were to accept that Jose was a sex abuser (the evidence is very weak btw) , I do not see any evidence that Kitty was a sex abuser , and she did not deserve to die.

She was killed because they wanted the money, and that's first-degree murder

I do not for a second believe that their lives were at threat. No one in the family can drive a boat, so they needed to hire someone to do it, and you aren't going to murder two people when there's a witness.