Is there a general ruling or part of the Comp Rules somewhere that explains that replacement effects are replied before "can't" effects -- or vice verca?
Not that I'm aware of and that is why I'm wondering. The way the ruling is worded, a judge could reasonably state that since leovold disallows the last 2 draws of ancestral recall, the replacement effect from notion thief doesn't apply and I would get to draw 2 cards in my scenario. In plain English that is exactly what the ruling states. Like I said, I have a feeling that is not the intent and not what they had in mind with that ruling. But barring some other rule we haven't considered if a judge encountered this situation and stated that my opponent draws 1 and I draw 2 he could point to this as his justification and have the backing he needs.
Under the heading: 101. The Magic Golden Rules
101.2. When a rule or effect allows or directs something to happen, and another effect states that it can’t
happen, the “can’t” effect takes precedence.
Example: If one effect reads “You may play an additional land this turn” and another reads
“You can’t play land cards this turn,” the effect that precludes you from playing lands wins.
Edit: Didn't see the above post until after I had written. @ChubbyRain's answer is the one.
Kalitas is a replacement effect, noted by the use of the word, "If". This means that the narcomeba going to the graveyard is replaced with the narcomeba going to the exiled zone. Narcomeba never goes to the graveyard and never triggers bridge from below.
If the wording on kalitas was 'when a creature dies and goes to the graveyard...' the when indicates a triggered ability meaning the narco would hit the graveyard, kalitas trigger to remove would go on the stack and bridge from below trigger would go on the stack and both would happen. But since he's worded with 'if' its replaced. Yes, kalitas can help shut down bridge from below.