Much of the heavy lifting is over. Philadelphia Flyers general manager Daniel Briere has done an admirable job setting the table for the organization to continue to improve. His work has already been validated, to a point, by the Flyers surprisingly reaching the second round of the Stanley Cup playoffs this past season. Things are looking up.The hardest part is yet to come, though. Briere’s most difficult task will be pushing a young, promising team to true contender status — unlikely to be accomplished without one or two splashy moves. This is the time on the calendar, of course, when those moves are typically made.With that in mind, let’s take a closer look at some Flyers roster questions with the start of free agency at noon on Wednesday fast approaching.Will they upgrade the defense?Based on what we know so far, it seems that the Flyers have prioritized improving their defense above all else — particularly after already addressing the backup goalie position by acquiring Joseph Woll from the Toronto Maple Leafs.The Flyers have interest in the Columbus Blue Jackets’ Zach Werenski, per multiple team sources. Colleagues Aaron Portzline and Shayna Goldman poured some cold water on that possibility on Sunday, suggesting that because the Blue Jackets prefer players that would help them right away, the Flyers might not have enough to get into the conversation. The Blue Jackets may not be interested in Matvei Michkov, and it’s difficult to see the Flyers parting with Tyson Foerster, who looks well on his way to becoming one of the better two-way forwards in the league (although for a guy like Werenski, he may not be untouchable). Further, if Werenski wants to win now, it’s tough to ascertain whether he believes the Flyers are in position to do that over the course of the next two seasons, which is how long he’s signed for.Darnell Nurse of the Edmonton Oilers is another player the Flyers have looked into, but it feels like he may be more of a Plan B than anything else. The thought process here is that the Flyers may be missing some nastiness on their back end, and Nurse would help to remedy that.Pending free agent John Carlson would make sense as a short-term addition to help the power play if he doesn’t sign with the Carolina Hurricanes, who just acquired his rights. If the Flyers don’t believe Werenski is possible, perhaps they’re comfortable outbidding everyone else for Carlson — something they’ve already shown they’re willing to do, such as when they signed Christian Dvorak to an inflated one-year, $5.4 million contract this time last year.Rasmus Ristolainen, who has been in trade rumors since what seems like the Harding administration, could be had for the right price. Briere even acknowledged as much in his comments after the first round of the draft on Friday, saying: “We know the situation with Risto. He’s got one year left on his deal. We’ll see what happens.” It’s tough to see the Flyers moving Ristolainen without adding another defenseman, though, as there remains some skepticism within the organization as to whether prospects such as Oliver Bonk and/or David Jiricek are ready for full-time duty.