The ones about Remus and Peter are fabulous. I feel like the ones about James and Sirius don't quite represent the characters. But it was still great!

These are really good, I think you did a great job! I especially like the ones about Remus and Peter

Oh no, you did quite well. The first two ones were excellent. The next three ones could use some improving. I am glad I inspired you. By the way, a haiku has a format. The first line is five syllables, the second one is seven, and the third one is five again. I just noticed that some of the haiku's do not follow the format. You have six in many lines.
For Remus Lupin, I suggest a revision that displays more why the moon burdens him. Something like:
The burden of the moon lay hard upon his heart disfiguring transformation. That is not a haiku, of course, but perhaps you can do something with it?
Have fun haiku-ing!