It does stretch credibility a tad. It makes sense the party would share tales of their exploits but the concept that every detail would be known to companions not there at the time seems a bit flawed if the only possible suggestion is the tadpole, which in itself as a story arc has plot holes and flaws at present. The companions might be ‘connected’ by the tadpoles but we certainly can’t see into every facet of eachother’s minds.
I’d like to see more consequences to your decision making rather than the have your cake and eat it too mechanics. If a companion can’t be present during a certain incident, then let it be. You can try them in another run through another time...that is half the appeal of these types of games: replayability.
There is of course a rather simple and much requested remedy for this situation: make a party of 6 possible.