Holy Town High School in Falaknuma for class 2 and class 4 joiners next year?

My parents live near Falaknuma, and there's a real chance we shift in with them from next June. If that happens, both kids change schools: our daughter into class 4 and our son into class 2. Holy Town High School is close to my parents' place. Do they take new students in those classes, and is there an entrance test at the primary level? I'm also wondering how children manage the switch from CBSE to State Board at that age.