Hi,
yes, I got my interview apopointment, finally after 2.5 month, I had to send them an email asking about releasing spots and after they responded, the same say I emailed, I was able to scheduled the appointment.
As far as your case number, I have learned that every case is different but i got my welcome letter with case number almost 3 month after my petition was approved. I found this video after the fact but I am sharing this with you as it might be helpful.