MIAMI — The notion of dueling dual timelines is among the factors that made the Miami Heat’s approach to this season particularly intriguing. Now, amid the mediocrity that is .500, that intrigue has been tempered, as appealing as Friday’s Thanksgiving leftovers. For as much as there was the unknown about how much Erik Spoelstra’s 30-somethings had left in the tank, how much more could be mined from Jimmy Butler, Terry Rozier, Kevin Love, there also was the intrigue of the next wave, those who would pair going forward with Bam Adebayo and Tyler Herro. Now, justifiably, there are doubts. Nikola Jovic as emerging starter?