I do have a refrigeration background, so here is how I would do it.
Start condensor system. Start compressors. Once desired psi or vacuum is acheived, start the pump and HX control. You didn't mention evaporators, but they should turn on when the pump turns on. If there are a lot of evaporators in the system, I would stage them on one or two at a time so as not to place a lot of demand on the system all at once. Every system is a little different and has it's own 'personality'. If this is a new system, there will need to be a lot of babysitting and tweaking to figure out what is best for your application. Good luck!