Zach Braff is the one that I find baffling.

Bojack never really knew him, as far as we see.

So what's he doing with people who are very personal memories, like his mom and Sarah Lynn?

Because everyone Bojack has dinner with in View is someone he wishes he could've been more like.

He is not just reflecting on the concept of death in general. He's asking himself, "if I'm dying now, did I have a good life?" and his way of answering that question is to imagine characters who represent variations of the person he wishes he could've been:

• Sarah Lynn: wishes he could've achieved her level of mega-fame or thinks achieving more with his career would've made him happy (or he envies her carefree attitude)
• Beatrice: part of him admires her strength and brutal honesty and wishes he had that, even though he disliked her, he respected her.
• This is why Secretariat and his dad are conflated into one person: they both represent the masculine/horse man ideal he wanted to live up to.
• Crackerjack is also, someone he never knew but is there because part of Bojack wishes he could've done something great with his life like made a personal sacrifice for his country or something similar.
• Herb is not just that he wishes he could've been a better friend, but he also wishes he could've been more like Herb. Herb has many positive qualities Bojack wishes he had.

The more puzzling characters become more clear when viewed this way: Zack Braff and Corduroy Johnson Johnson. Zac is the entertainer persona, the affable party guy, Mister Peanutbutter type, that Bojack always tried to be in social situations. Corduroy either represents a desire to have been a better co-star, or his wish to have found solace in religion. Maybe he just saw that Corduroy was a good guy and fun to work with, and he had always hoped to be that encouraging to his own co-stars, but often failed to be.

You can interpret each character in the dream as representing something Bojack wished he either was or had had in his own life. He's working through envy. Envy in CJJ's case is like wow he believed he has meaning and higher purpose, I wish I had that.