Yup I agree. Whatever the strongest hands with blocking capability that we are folding should be 4bet. AJo and ATs are a call in this situation vs most buttons, so we can go ahead and 4bet the A2s-A5s like you suggested. I originally wrote the post dealing with UTG vs button and decided to change it to hijack due to buttons possibly wanting to flat hands as strong as QQ vs UTG opens and mentally didn't adjust the 3bet calling range to wide enough.