The marriage of a Princesse de Ligne with a Comte de Dampierre is not Ebenbürtig, it is not a marriage between partners of equal rank. However it is Standesgemäß, a marriage between partners of an equal standing: Alix de Ligne comes from the Belgian aristocracy. Guillaume de Dampierre comes from the French aristocracy. So they are Standesgemäß.
In some Royal House, like Prussia, the norm is to marry Standesgemäß, it is not at all needed to marry Ebenbürtig there. The marriage of the late Prince Louis-Ferdinand of Prussia with Countess Donata zu Castell-Rüdenhausen was Standesgemäß and therefore dynastic. The marriage of their son Prince Georg Friedrich with Princess Sophie von Isenburg is seen as Standesgemäß and therefore dynastic.
So we need to know what exactly is the requirement for a dynastic marriage in the House of Brazil. Is that an Ebenbürtige marriage (strictly equal) or is it "only" required to marry Standesgemäß ?