As to your question: the only way I found that I can reliably ensure that the sim ATC works is to create the flightplan in simbrief, download the .pln import that to the World Map planner, ensure to select a departure stand from the drop down menu and NOT the map (if you do that it will create a new flight plan that will most likely not match the simbrief one). Once in the sim you will find the FMC pre-loaded with departure runway and SID/STAR and no need to import from simbrief. The only (slightly annoying) difference is that all waypoints will be shown as DIRECTS and not VIA (Airways) in the flight plan. You can always still import the route from simbrief. You will then get the sim ATC synched up.