MagicU gives two achievements, but I suspect that you do not get the girl. Save before last day in MagicU as achievements are on two opposite choices.

Below dialog choices with Narika give you enough points with her to make her accept MC as heist partner. Choices in MagicU do not give you enough points, if you went the wrong way in chapter 2. Wrong chapter 2 choices might even put negative modifier in final result.

Ninja hunt 1
-> "Put her down"
-> "Mock Narika"

Ninja hunt 2
-> "Do you have a boyfriend?" -> "I believe you"
-> "You're going to lose"

MagicU
-> Do not piss off the dean or you lose access to MagicU.
-> "Ew, no..."
-> "Tell her the truth"

You could do good run and check if all three join brothel on their free will, but at this point I would suspect that best path is to capture Narika and Haruka, go along with Mizuki and make Homura join willingly or by force. Some conditions in final chapter 3 boss fight are set only for one ninja ally.

Unless MC changes that in chapter 3. After all she is fire kunoichi in disguise.