In summary, you appear to be asking us not to judge the non-ECNL DA clubs' performance yet, because they are going to get a lot of ECNL players joining them in July.
Between commitments to prior teams, ODP training, school and family conflicts (prom, graduations, etc.), vacations, and injuries, my experience is that the roster issues faced by each team in June (and throughout the summer) tend to average out, and the performance of these teams is a pretty good indication of what their seasons will look like, with few exceptions.
Also, DA tryouts (even for olders) began almost 2 months before this showcase, non-ECNL DA clubs have been actively recruiting ECNL players since the DA list was released, and ECNL players are free to tryout with other ECNL clubs May 1st, so I respecfully disagree that rosters are far from finalized. If a team is in need of an impact player at this point, or trying to fill a gap in their starting 11, the coach has not done his/her job, and/or the team needs to adjust its expectations.