Each has its own separate star count, so playing the levels on beginner won't have any effect on your progress in pro mode. (slidetoplay.com)
The new guidelines state that low Star count or play count after a certain period of time will get your level deleted, as well as levels that feature bugs or broken elements. (mariopartylegacy.com)
Mini Ztars, the purple counterparts, will deduct from your overall Mini Star count and should be avoided at all costs. (mariopartylegacy.com)