My parents have supervisa already. I am dependent can I apply visitor visa for birthday party .how much percent chance I got the Visa .can ur advice me about this Visa beacause I am too much confuse I should apply or not .
Can't say for sure what your chances are.
You mentioned they asked for dependant educational documents in June 2017. If they have a doubt about your eligibility as a dependant, your chances of getting a visitor visa might be low.
On the other hand, if they are satisfied with the documents you have submitted, your chances of getting a visitor visa might be high as you will eventually get PR under family class, so the visa officer may not have to worry about you overstaying your visit.
At the end, it depends on the visa officer reveiwing your visitor visa application. So you can either try it out and see or play it safe and wait for a decision on your PR application.
again, ask your sponsor to get in touch with their MP and put an enquiry in. They should be able to find out what the status of your application is and go from there.