Thank you very much for your complete message, it will help me.
I will begin another invention with a better structure. If I understand correctly, for an invention it could be good to use a A, B, A (A = main key, B = dominant key) ? And between A and B section I have to find a modulation chain ? I will also study Bach a lot.
Technically is my counterpoint correct ? I learn by myself so I have no teacher to correct me.