But how much can they tailor the defense to particular strengths without sacrificing what they hope to achieve schematically? It's the player vs. system argument, and Kelly seems very much a system guy.
After a look at Kelly's first open practice, it's safe to say that Davis' defense will have an elemental 3-4 look up front and that both outside linebackers will be asked to pass-rush and drop into coverage.
"If we're playing in a three-down [linemen] scheme, our outside linebackers will be asked to do both things," Kelly said. "But we have to figure out who that is, and that's part of the whole process."
Cole and Graham - Phillip Hunt can be thrown in there, too - have never been asked to play outside linebacker in the NFL. Cole would drop back occasionally when former coordinators Jim Johnson or Sean McDermott dialed up fire zone blitzes, but it wasn't very often, and this is an entirely different thing.
Davis' outside linebackers won't have their hands on the ground often. They will pass-rush from a three-point stance on occasion, but they need to stand more often than not because they have coverage responsibilities or because Davis wants to disguise his fourth pass rusher.
As cover linebackers, Cole and Graham need to "read" more than they ever have. They used to just pin their ears back and rush. They will have to learn to play zone, set the edge, and cover tight ends, running backs, and sometimes even - gulp - wide receivers.
"You might see me in coverage all the way downfield," Cole said, "but we don't want that."
Kelly said he thinks they can do it.
"You watch how fast they run, their ability to open their hips, and they just haven't been asked to do it, I think, because they were brought up as defensive ends," he said.
Kelly noted that Graham played outside linebacker in college, but Graham said he was asked to drop back "probably three times a game" at Michigan. The 42 times Cole dropped back in 2010 - out of 962 snaps - were the most of his career.
Connor Barwin dropped back on 101 of 1,137 snaps last season in Houston. He is the only one of the outside linebackers mentioned to play in a defense that ran odd-man fronts.
"It's definitely an adjustment," said Barwin, who was signed as a free agent in March. "But if you would have looked at the first week when we got here for minicamp and looked at the way Trent, [Graham], and Hunt are dropping now, they're three times as good as when we first started."
Barwin looked the most comfortable in coverage on Monday. He once ran 25 yards downfield and kept up with running back Bryce Brown. But it was just one day, and the Eagles were working only on fundamental plays.
Maybe the Eagles plan on utilizing promising defensive tackle Fletcher Cox as the Texans used J.J. Watt last season, asking their outside linebackers to take on more blockers.
The defense is obviously a work in progress. Kelly may be willing to work with what he has now until he gets his desired players. He wants long, versatile defenders.
Cole and Graham aren't long. They both have lost weight. Cole said he weighs 266 pounds and hopes to play at 260. Graham said he is in the 270s and wants to be almost into the 250s.
The jury is still out on their versatility.
Cole played some defensive end, as well, on Monday, but it's another change for the nine-year veteran. He said he is excited about his new role, as did Graham. Of course they did.
"It's fun for me," Graham said. "I'm excited. As long as I'm able to maintain the weight, being down and running around, I should be all right."
Contact Jeff McLane at firstname.lastname@example.org. Follow on Twitter @Jeff_McLane.