As described in first situation, I think you have it right, E-9 & no RBI, assuming routine fly to right that should've been caught with ordinary effort with two outs to end inning.
If less than two outs, I would score a sacrifice fly & RBI reached on E-9, assuming the runner would've scored if the ball was caught.
In second situation, I score single and one RBI for sure. If R2 was never held up, I score 2 RBI. If he was held up or slows up & gets sent after, I score an E-7 and no RBI. You have to be there, which means "up to you" as the scorer. Would he have scored with ordinary effort, yes=rbi, no=error.