Seemingly every member of the Spider-Man: Miles Morales writing team has made themselves known, and it's obvious Insomniac Games has brought on some new blood to tackle the upcoming project. Most of the individuals involved with the writing staff had nothing to do with the original Spider-Man PS4 title.
Shortly after the Spider-Man: Miles Morales announcement trailer aired, Evan Narcisse, Mary Kenny, and Ben Arfamann all took to their personal Twitter accounts to confirm their involvement with the game. It's assumed these three make up the full team because three was the same number that worked on Spider-Man PS4. There could be others that just haven't said anything, but it's unlikely.
Both Evan Nariccse and Mary Kenny made names for themselves as journalists, with Nariccse writing for publications like i09, and Kenny for The New York Times. Both also once wrote for Kotaku. As far as narrative credits go, Evan Narcisse penned the script for the Rise of the Black Panther comic series that ran in 2018, and Mary Kenny was the head writer for Telltale Games' The Walking Dead: TFS, which, funny enough, also released back in 2018.
Ben Arfmann is the only writer returning from Spider-Man PS4. Jon Paquette, one of Arfmann's partners on the project, confirmed that he's not involved with Miles Morales, proclaiming in a tweet that he's excited for those who are. The third writer for Spider-Man PS4, Kelsey Beachum, hasn't said anything on the topic at all at this point.
As it is right now, there aren't many details about Spider-Man: Miles Morales' story. Insomniac Games Creative Director Brian Horton has only given a brief synopsis of it. What supervillains will show up, and how vital a role Peter Parker's Spider-Man plays throughout the whole thing remains a mystery.
It's clear, however, that Miles Morales serves to introduce Miles' Spider-Man into the Marvel's Spider-Man video game universe, and set him up for whatever role he'll play in the upcoming Spider-Man 2. The game doesn't have an official announcement yet, but Brian Horton has said that Insomniac still has stories to tell with Peter Parker, which means a Spider-Man PS4 sequel is inevitable.
Kelsey Beachum and Jon Paquette may not be working on Spider-Man: Miles Morales because they're currently preparing Spider-Man 2's narrative. This idea is certainly possible with the way Horton describes Miles Morales and words his Peter Parker statement.
Spider-Man: Miles Morales launches exclusively for the PlayStation 5 in holiday 2020.