If
you say "Based on angle of throw and position of batter runner defender was, in my judgement, interefered with" then it was INT as long as the BR had reached he lane, so why the question?
All, visualize a throw from the 3rd side of HP, over a BR who is in FAIR territory, but low enough to be caught by the fielder except for the view blocked by the BR. I think that is what the OP is about. Then, if the BR had reached 30' and blocked the view of the fielder or contacted the ball, I say INT.