Update
Installed the Wix filter last night, fixed that leak. The Wix filter is definitely higher quality than the generic filter that came with the kit. The strap holds it nice and firm compared to the generic one which was pretty loose. But the best part was fixing the leak at this location.
We ended up hammering the tank in two spots so the 45 degree fittings didn't make contact and put any side load on the supply and return. Then we pressured up, still leaked from the supply. So we took the male/male fitting off and applied Permatex Aviation sealant, reinstalled, pressured up, still leaked (see picture). But we realized we were rushing the Permatex so we reapplied, let it set a few minutes, then installed. It has to sit at least 4 hours so we'll pressure it up tomorrow night and see what happens.