I'm kind of confused about the winner and what rules that appiles this time. Is it confirmed that the winner will get a separate solo single or will it be a track on the janken single? The differencies are quite important.
If the solo is part of the the jaknen single it won't matter too much if she is popular or not, they will just switch focus and attention from the solo to the b-side. If it is a separate solo single it will be a huge difference in budget and promotion depending on her popularity.
Everyone's first reaction when they heard about the solo was probably Sayanee and rigged I can't imagine that management would be that utterly stupid to go through with such a stunt. Her history and complete failure during all previous NMB preliminaries in contrast to suddenly win everything would rise an eyebrow or two. They do not need this janken excuse for her solo debut at all. And, it would totally ruin her credibility as a person and leader to accept such a deal. In short, really bad for business as Sayanee would lose a lot of fans.
Sucks, but she isn't allowed to win
It was brought up already but the possibility of Sakipi vs Sayanee for a spot in senbatsu is problematic. This tournament was created with someone like Sakipi in mind. So, oshimen that got everything vs the super nice girl with nothing I would actually prefer that Sakipi won this fight as it would benefit NMB more and give her some well deserved attention ( and ease the conspiracy theories ).
Possible epic moment if the two actually would rig this fight openly on stage to give Sakipi the senabtsu, or at least get the offer openly just before the fight.