I was able to upload this roster into the newest 1.2.0 editor. Name changes in OFFLINE mode work. The reason why this roster file was freezing when initially loading up a quick game was because all the teams had 12 or more tiered players and the limit is 11. When I adjusted all the team tiers to 11 or 10, quick games loaded and played with no problems.
To get this file to work in Season Mode, you have to use the new Division option on the team tab and designate 8 teams to be in the Pacific and Atlantic East divisions which exist on the editor but not in the game, essentially hiding these teams. Then distribute the remaining 24 teams evenly among the six divisions and season mode will work.
However, it won't work perfectly...I used the Chiefs...and they were duplicated, listed twice in two different divisions. Funny thing is, the season didn't freeze when I simmed through it. Instead, the Chiefs record and player stats were doubled....they finished 22-10, Jamaal Charles had 3500+ yards rushing, Alex Smith threw for 6600+ yards and Dontari Poe had 26 sacks.
Haven't figured out what caused them to be duplicated in the game yet. Also, even though you set the divisions in the editor, the game still allocates the teams to which ever division it chooses. Nonetheless, quick games work and season mode works (for the most part) with previously mentioned tweaks.
I hope this helps.