Hi!
I see that you want to develop a website with machine learning capability for assessment & profiling of students ability. Such a system would not be easy to develop, but not impossible. I have some insights:
1. The system will need a sizable data bank of questions & test packs with their answer, timing, hints, etc. That means the system requires large database and considerable time to prepare the content of data bank.
2. To accommodate the many factors in the scoring system, the formula will have many variables with weightings etc. Complex formula (or simple formula running on a large database) requires high computing power.
4. In my opinion, a scoring system like you described can never be 'extremely accurate', due to the factors such as lucky quick & correct answer, deliberately choosing wrong answers, student's health condition during tests, etc. Even when the scoring system is applied in a period of time to gather statistical information or trend, we should regard the score as an estimation.
I am a software & web developer with a background in engineering, proficient in Microsoft platform (.NET + MS SQL Server) and PHP + MySQL platform on frameworks such as CodeIgniter, with UI frameworks such as Bootstrap. And many times I also responsible for the graphic design works. I also develop mobile applications in Android platform.
I live in Indonesia, my timezone is GMT +7.
I look discuss about this project with you.
Thank you.