Application for licensure or temporary practice permit?

I'm accustomed, over the years, to temporary permits being very short-term -- only good while/until the state completes your background checks and issues your permanent license -- so there would be no question of "choosing" between a temp permit or permanent license. The temporary permit is simply part of the permanent licensure process. (Of course, PA may do something entirely different -- I've never lived or worked there.)

You don't have to give up your TN license in order to be licensed in PA -- you can maintain as many different state licenses as you want to pay for (and meet the CE requirements, etc.) You can hold your TN license, once you've moved to PA, until it expires and not bother to renew it, if you don't need it any more at that point, or, if you think you would have a reason to continue to hold the TN license, you can renew it and keep it current, even if you're living and practicing somewhere else.