Well definition of parallel leads show means two or three leads and their respective stories..
Examples of parallel lead shows are ek hazaaron mein meri behna,swaragini,veera,sapne suhane ladakpan,ishqbaaz etc ..these shows are about sister's , brother's and their respective stories ...they were all present on the montages for those shows..Ishqbaaz was exception bcz Gul played fans by showing only shivika😆
Coming to yrhpk..from the very first promo, show was promoted as story of mishti and how she deals with jhatpat shaadi....later promos released with abir and mishti and till date it's promoted as their love story ...so proper leads or to say only leads of the shows are MishBir ..kuku are second leads not parallel leads as they are shown as siblings of leads and they did gave a good start for their love story though they totally stopped showing kuku story after baba track for god knows what reason...
And abir himself said to nishanth in one episode that it was abir and mishti's story and it will remain theirs....and frankly even though MishBir are leads one thing I liked in this show is they focus on every relationship and every character and their dynamics.
P.S .. I know it's not needed but wanted to say , though MishBir are leads ..this show till it lasts will be mostly shown in mishti's pov(few exceptional scenes and episodes) like any other itv show ... everyone who watches yrhpk should accept it including me bcz at times I want to see things from abir pov but it's rarely shown😆