How long does it take --- is a million $$ question. Unfortunately you may not find any specific answer anywhere because of different data points. The process depends on stream, your personal history , travel history, Criminal checks, Security Clearance and finally CIC agents/Officers. If we are fortunate, our file gets clearance from everywhere so fast. Otherwise, we have to wait patiently until our turn.
Regarding the process between NN/NA-IP -
In the initial check, support agent will quickly verify the uploaded documents and make sure that nothing is missing. At this time only our medical status will be changed to PASSED. He will also send out documents for R10 Review. Here, the background check status will also be changed from NA to IP or Next step to conduct BG Check.
The Next agent will pick our file and do R10 validation. During this period, some of the applicants may asked to provide RCMP. Once he confirms R10 is done, Criminal verifications are done then our file move to next stage. In this stage, agent will initiate Security check and also starts Eligibility Assessment (A11.2). Once he done with these checks, he will provide his recommendation for A11.2 and the file will transfer to LVO(Local Visa Office).
This time our BAG status is will be changed back to NA.
Once they receive Security Clearance, Officer at LVO will review the agents recommendations and approve our application. At this stage, they will change our BG status to In Progress. After this status, we will get PPR mail if we already paid RPRF upfront.
Hope it helps you.