We the information we have so far, the only that changes would be who we call MC's sire. It also implies that we have confirmation that MC's sire is involved with him, as she is clearly showing interest.
But, while we have no direct confirmation that redhead is sire (nobody saw sire fed MC's her blood), we have a large amount of evidence suggesting it. The only reason so far to think otherwise is if dev themselves are trying to confuse us. Besides, in VTM and most vampire lore, the blood ties you not just to your sire but to all above the bloodline.
If anything else, the other difference is the following. Under the standard assumption (redhead is sire, red dream beauty is vampire ancestor of both sire and MC), the order of power is essentially red dream beauty> sire> MC. On the alternative hypothesis, redhead is not comparable to the other two, and we only know red dream beauty>MC.
Obviously that is an extreme simplification, as it is not just generation but how old you are as a vampire that affects power levels. MC seems to be a lower generation vamp, but Sharon is currently stronger that him. Well to be honest, we know next to nothing about Sharon's bloodline and vamp heritage, neither we know about MC's. This is just under the current assumption we are all making about MC clearly being strong, but that was also born from the assumption that redhead is sire and her conversation being super old.