1) This more stable design of the F-35 presumably makes it a good strike aircraft or are targeting devices so good these days that it's irrelevant (I imagine not, but..)?
Define stability. Why do you say the F-35 is more stable?
2) Depending on the answer to the above, making Typhoon an all-rounder must take a lot of expertise and making the F-35 a 'fighter' a similar challenge?
Why is the F-35 deficient as a fighter? Please tell us.
... Are you merely repeating things you've heard at nth hand on some other aircraft chat board? That's not a good habit.