Even on the first of the game, they have proven that Mbappe and Messi can be even more than a complete team for PSG during the first half PSG scored three goals and made the second half easier for themselves while Mbappe scored two goals and one assist but Messi scored one goal and two assists this can show us how these two players are perfectly working together and make each other complete.
Mbappe gradually realized that he won't be able to bring PSG to titles if he is the only super star attacking player in PSG. He needs Neymar and Messi to support him and to win trophies together especially Champions League. With Neymar and Messi support, Mbappe will receive more key passes, more chances to find more goals for his personal record.
You're right, I really don't know if Messi will let him go, by Neymar if he may leave, however with the injury he has now it is likely that it could happen, of course he is now undergoing treatment to get better, although Ney he always gets injured in the same ankle and well that is like his Achilles heel
Neymar has gotten many injuries with his ankle and such injuries always make him feel so bad. Usually such injuries require a few weeks or months for Neymar to come back and more bitterly, such injuries occur around important matches which Neymar does not want to miss.
I am not sure that Neymar will be able to join the second leg match with Bayern Munich in March but perhaps he will miss it, another important match he misses by injury.
Amazing performance from both Messi and Mbappe, this duo is insane. Defeating their biggest opponent with 3 goals in their own stadium is just the best thing they could do, I think French league champion is obvious now. If Marseille won this game they might have a chance but PSG showed everybody that they are on a different level. This league is just too easy for PSG.
These duo attacking players combined well and it is good for PSG before a re-meeting with Bayern Munich in Champions League in March. This win is important for PSG in Ligue 1 too because Marseille is one of their direct competitors for Ligue 1 title. Getting three points and making a direct opponent fall down in sentiment and confidence is good achievement.