Visa application after first refusal with no major change in situation [closed]

It's always been my dream to visit the UK. I first applied for a Standard Visitor Visa in Summer 2015 with only a history of one trip to Istanbul on my passport. I had previoisly been refused 2 Schengen Visas due to mistakes in paperwork.

I am Lebanese, and a medical student, I put in my parents bank account as they would be my sponsors for the trip. My father is a doctor and the bank statement showed around 50 000$.

However, I got refused on the basis that the bank account didnt have enough activity on it, that they see little point in the trip and that they had no proof I was going to return to my country.

I am now reapplying to go spend New Years there. I have since then acquired 2 Schengen visas which I've used to visit Germany, Spain and Greece, as well as going on 2 trips to Turkey and 1 trip to Cyprus, all for a few days tourism.

I still have an ongoing Schengen visa until Feb 2017. Seeing as my situation as a student hasn't changed, I am worried that I cannot make any major changes to my application and I'm unsure how to go about it. Other than including a letter saying that I am enrolled at uni and that I will be receiving my diploma at the end of 2017, I have no other way of proving my attachement to my country. I have included my own bank account that has 12 000$ in it, and explained that since I'm still a student, my parents put in money every month in my account. I also included my dad's bank statement for a different more active account that has around 5000$ in it and a letter that says he is sponsoring me. I said in my application that my father will be contributing 1000$ to the trip and I have a letter from the bank saying there has been movement in the account for about 66000 since the beginning of the year. I have a work contract that proves that my father is a doctor, but not how much he gets paid and how.

An invite from a family friend who is a British citizen and says will accomodate me for 3 days, with a copy of their PP. Flight bookings.

Is it necessary to provide a tenancy agreement for the house I'm staying in? The person inviting me lives with his parents and the house is in their name. Is it necessary to provide more details about where my father gets his money from? This would be very hard as most of his work is clinical and cheque related. Any papers missing? I want my chances to be as high as they can be.