You cannot go back to your home after you receive P2 but you can even before P1. All you have to mention there is, you're not in the country and you have to mention your expected date of return. Until then, your application will be on hold.
Looking at the processing times right now, I would advise you to delay your visit until the PR card. Ya'll have waited for long and now you guys want to cause another delay in your application at the end? Does not makes sense to me. Rather wait and get the work done that waiting later again after.