Looking amazing! keep up the good work.. and I don't even wanna know how much we've spent on just live food for our gar... but it really does make a huge difference. I would def keep trying floating foods in particular at night even if they don't take them right away. should help build a routine for them and get them eating pellets sooner then later and cut food costs for you. I found useing pellets best as the "feeders" would eat any uneaten pellets themselves and essentially stay "gut-loaded" for our gar, and little to none was left to rot in the tank ( simply scooped/syphoned any out during water changes.)
btw expect abit of fin shredding as they get older and develop a pecking order. like most predetory fish they will cannibalize any stunted/significantly smaller fish, but ime they develop pack-like heirarchys when kept together long-term... no visible aggression a majority of the time, but every now and then the dominant fish gets tested, fins get nipped sometimes shredded. As long as it's not consistant i found leaving them together worked best.