Also known as the winter break, the first-semester break marks the start of the late game.
From this point on, increasing Lennard and Albert's favorability becomes more difficult due to their graduation.
They only show up in a few special events when invited by the academy.
Thankfully, the fact that they never canceled Isabella's enrollment or locked her up like in some scenarios shows that we did a good job keeping her away from trouble and maintaining a good relationship with them.
In other words, we avoided the bad endings caused by her brothers.
We still need to be careful, but the three appear to be doing quite well now, so the chances of them acting this way against her are pretty low.
As for Isabella's other relationships... It's hard to say.
She usually spends some time with Edmond in the library, as he was interested in catching up to her scores and asked her to be his teacher.