The deceased children Manny meets in Year 3 have little wings on them, making them look like angels. In Mexico, Day of the Dead is for the adults (Nov 2) while the day preceding is to honor the departed children, known as 'Día de los Angelitos' or "Day of the Little Angels."
You can hear an announcement for lost baggage belonging to a H. L. before you get the briefcase for Charlie. That is the briefcase of Hector Lemans, which explains why Charlie wants it back so badly.
If Don Copal was taking orders from Hector why was he demanding Manny get premium clients or risk being fired? He must have known Manny had no means of doing so.
It would be reasonable to assume Copal had no reason not to be hard on Manny for poor work, even if he knew there was no way for him to do better. Anything less than his usual hardass behavior would be suspicious. Alternately, he wanted an excuse to fire the guy.
Also, this means that Hector can approach Manny for recruitment into the gang. Desperate people will do anything. My guess is that Domino would have approached him with an offer at some point, if Manny hadn't stolen his client.
Burning beavers (in't it a great name for a band?) are able to swim in a river of tar without setting it on fire.
Being on fire is what allows them to swim in the tar - you put out their flames, they sink instantly. Presumably it's not hot enough to actually light the tar.
Celso Flores had to go through the Petrified Forest equipped with nothing but a cane, while Manny went through it in a car. How did Celso reach Rubacava before Manny?
You're driving through a hidden tunnel, and a place full of burning beavers, and then some winding roads. You don't encounter Meche or Celso, so I assume the walking path is different than the driving path. Also, Celso has a compass in the stock, so the road isn't as winding for him. And lest we forget, Glottis ripped out his own heart, delaying Manny even more. I think we can all assume that he wasn't as delayed, and that's why he reached Rubacava first.
In the conclusion of the game, Chepito decides to walk himself to the afterlife, heading into the Number 9 Tunnel before Manny returns to El Marrow. Considering the game ends with Manny boarding the Number 9 in less than a day from then, the train travels 4 years in four minutes, and Chepito walks pretty slow, feel free to draw a conclusion as to what could happen to him.
You completely missed the point. Of the ENTIRE game. The Number Nine takes four minutes to complete the journey from El Marrow to the tunnel. Walking from El Marrow takes four years (as demonstrated by Manny's journey), then it's just a formality of entering the tunnel. Chepito could be gone the second he enters the tunnel and he might not even go to the same afterlife as the train. No-one knows.
How long have those Angelitos been trapped? And what happened to their parents?