The name Pilipovic can be found in the Kladusa region of northwestern Bosnia Hercegovina among Bosniak (aka Moslem) Bosnians. This area is mostly populated by the descendants of Moslems from neighbouring regions of Croatia, but also...refugees from as far away as Kliski Sandzak (Dalmatia).
The dialect of our ancestors (mine were from there as well) is the closest you'll find to the vernacular of Dinaric Croats: Ikavica.
Thus, based on all historical, linguistic and cultural evidence, I very much doubt the possiblity of a mass conversion (to Islam) of Vlachs (or Serbs) from the Ottoman occupied regions of Croatia.
Our Serb neighbours spoke a dialect (although not much different) which was much closer to the vernacular of Montengero and Sandzak regions.