Greetings,
I am a certified DELF exam scorer for five years now. So, I can say that the DELF B2 is closer to the AP language exam. In fact, I would even say that the B2 exam is easier than the AP exam. Any DELF B1 and B2 exam practice books would make nice supplemental activities for your level 04 and AP students.
I can only echo the description and response given by Laurence Ervedoza Patrick. For our students to achieve more and more quickly, we teachers will have to teach our students to decipher and guess logically for the main ideas and general meaning from the start of level 01. We have to expose grammar forms more quickly so that students can increase their competencies in reading and listening. Production takes longer and pair speaking activities are great.
This past year, I had a French IV-AP student whom I taught from level I thru 4 to score a 4 on the French AP Exam. I am very proud of her. At the beginning of the school year, I had only predicted a score of 3. So, I know that what I do in class pays off in four years.
Cordialement,
James O'Donnell