Isaac II is pretty funny in that his first act as emperor was to issue a tax to finance one of his weddings. His reign is in the era of the founding of the second Bulgarian empire.
In any case, those are definitely representations of the same person. Isaac II married Margaret of Hungary in 1185. (Yes, she was that young.)
Someone gave the one profile of Herine the birthplace of Margaret. Eirene/Herine's origin is not known. (Although of course there has been much conjecture based on what is known.)