In responding, CRL was the issue, so I assume we are talking about teams that are Flight 1 (SCDSL) or Gold or Premiere (CSL) in the upper-echelon and playing against other higher-level teams. My response assumes these teams are made up of athletes with a future and not Flight 3 or Bronze or Presidio teams:
1 (fields), if that is the case, then great. However, most clubs have to contract with their fields when needed, especially if playing at a School District field and don't have standing orders.
2 (EMT and Trainers), for State and National Cup, CRL, ECNL, CSL Premiere and the DA (i.e. high-level level games) EMTs and Trainers are available. I can understand no medical on the field for practices and/or scrimmages and/or Flight 3 or Bronze play (i.e. glorified recreational ball), but not having medical on the field for Flight 2 and Silver and above when kids with futures are playing is negligent. The Development Academy can't even start their games until the trainer has introduced himself to the coaches and requires 2 trainers for every 4 fields when they have their showcases. Coaches and Parents have an inherent conflict of interest (tend to encourage the athlete to tough it out and play) and are definitely NOT first aid qualified. I have my Grade 8 and E-License and take the "Concussion" Certificate every year, which makes be barely qualified to state "Hmmm, looks like a concussion, better see the EMT or Trainer."
3 Field Marshall is required to settle disputes, confirm eligibility of players and coaches, report scores, take protests, etc. The Field Marshall also enters yellow and red cards and handles the reporting.
4 Referees. Yes and No. This is not a scrimmage. The Referee Coordinator for Cal South is Leo. Leo contracts with the various referee associations and provides the coordinators. Each association makes the assignments and the assignor is paid by Cal South. The on field coordinators are an important element whenever there are more than a few crews and operate as a backup referee in the event one is injured or doesn't show. For low level games with little on the line, I agree that a coordinator is not needed. For high-level games then you need a coordinator if you have more than a few fields, or a very experienced Ref if a one off game. When parents or coaches are removed, its the Coordinator's job to see to it that happens. Now, the problem you are going to run into is the best crews are "supposed" to be assigned to the more important games and typically are assigned to at least two, but preferably three games. If you start running multiple venues with just a game to accommodate two local teams then expect to get a bottom of the barrel crew (i.e. whoever wasn't good enough to get assigned to the tournament venue)