French long stay visa

Hi everyone, I am a prospective Erasmus student coming from Italy ( not European citizen) to France for traineeship. I have applied for French long stay visa and have my appointment in 2 weeks. I have already acquired accommodation and most of the documents needed. I want to know if I still need Convention de Stage? Because mine is an intra-university internship and hence I was told I could bypass that document but I want to be sure.

Another thing, do I need a health insurance? Could you suggest me some cheap/budget friendly health insurance plans for the visa requirements.