As part of their input for your student’s common app, the counselor will provide a school profile that will put the school into context (how many AP classes are offered, how GPA is calculated, how many students pursue post-secondary education, etc.). They will also provide information on your student specifically - GPA, class ranking, rigor of classes, etc. If you dig around on the common app website (or here on College Confidential), you can find the forms the counselors have to fill out. I believe the counselors can see where the student has applied but not certain. They do not receive
As for recommenders, they upload a single letter for the student that is part of the student’s application to each college. The student can select which letters go with which application. For example, some colleges require only one letter from a teacher and others require a letter from a STEM teacher and one from a humanities teacher.
I do suggest that the student sends the recommenders information about what they are interested in studying, which schools they are planning to apply to and more details about their background - including a resume if they have it. My daughter asked teachers in person and then followed up with an email with specifics (how to upload letter to common app, due date, etc.).