A 90 minute connection going from the USA through CDG, while doable, if all goes well, is nearly impossible, particularly if your friends aren't flying SkyPriority to use the Acces No1 lane at immigration. It's been a train wreck the last 3 times I was there, and I AM SkyTeam Elite Plus / SkyPriority!
AND... If Delta has a schedule change making the CDG arrival a little later, fuggedaboudit!