Resident Evil Film Series [closed]

I am really a die hard fan of Resident Evil film series. I watched all series recently to get exact know-how of the plot of series and it seemed to be in a progressive and fluent way.. But there are some things which confuses me;

1. Albert Wesker is shown as Umbrella Employee as said by Alicia Markus in Final chapter, but in Extinction, he is new Chairman of Umbrella Corp.?
2. Dr. Alexander Roland Issacs is the co-owner of Umbrella alongwith James Markus and was safely upgrading underground for all these years alongwith other Umbrella committee, so Dr. Issacs that is in Extinction or previous films was a clone because in those parts, he was answerable to Wesker but in Final part, Wesker says he is loyal to Issacs?
3. Last question is of T-virus, it seems a good answer what I found here in other question that Ashford made it and Markus as head of Umbrella might have took it from Ashford to make his daughter healthy again because I agree that Alice also said in Final Chapter that he discovered T-virus not created it. But is this right? If yes, then from where it can be verified because film series and game series are a bit different by plots??
   Please reply to these 3 questions.