Help with 8~10 MongoDB Aggregation Queries

We are using MongoDB and handling Aggregation. We are looking to write queries like 1. Daily Active Users, 2. Monthly Active Users, 3. Weekly Active Users 4. User Session Length (Averaged) 5. Session Frequency 6. Retention rate over day and week 7. New Users Per Day (to be fed to a line chart), 8. Daily count for a specific activity in our DB. I will provide a list of about 15 top activities for which we need daily count. 9. Total time in app per day (averaged) 10. Top exit views i.e last view in a session (Sum per day) Please feel free to contact me if you have experience in mongo DB querying with expertise in mongo aggregation framework and query optimization. There are only 2 collections to work on: * users * user-activities I’ll provide same for both. This is a super urgent work, need this within 12 hours or faster. If you complete this, I have a ton of more similar work. Thanks