Firstly, there is questionable wording in the passage itself:
as he only had been interested
...in this sentence, would be better phrased as:
"...as he had only been interested..."
You're choice of verb forms seems perfect...
Let me just pick this out and let's see what others think:
"...to come to a lesson next week, to see what the pupils had (to have) to learn."
'had' or 'have'?
Non-native speakers : careful!