How many RBI

should the RF have made the play with ordinary effort? If so then E9 and no RBI's.

second situation. 1 rbi and an e7 on the left fielder for muffing the ball which allows the second run to score.

Both a little tricky.
first, was he running the fly ball down and didn't get it in time. if so, 2 rbi and base hit.
if he moved in the course of a routine play, error no rbi, no hit.

second, one rbi for sure, if coach would have sent him prior two rbi for sure. in this case, error on fielder let him score with no throw. again, was the hit reasonable to pick up if yes error, if he was running to his right and stopped it from going to the wall, it was not reasonable to catch and throw, so 2 rbi's.

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.