The player doing the Obey makes all the choices and card flips.
A Walk action cannot exit an engagement range, a Push or non-Walk movement can exit an engagement range, however you cannot declarea Charge (which is a Push) while engaged. So, if at any time during the Walk move you become engaged by an enemy model, you cannot continue the rest of the Walk move out of the engagement range of that model.
In Standard or Wedge deployment, you want one model on each of the table edge on the centerline. In Corner or Flank deployment, you want one model on each of the table corners on the center line.
Good luck on the translation! We all love Mark-Paul Gosselaar, so thanks for that!