Generally speaking, as don pointed out, brand A does not play well with brand B. The exceptions are broadly of two types, notification appliances and conventional devices on a specialty module.
Simplex panels have the sync protocol for a number of providers notification appliances in addition to their own, System Sensor and Wheelock for two that I know of. They may also do Edwards.
If there was an old conventional Edwards panel previously in place, those devices may now live on an addressable module from Simplex which is designed to turn a string of conventional devices (pull stations, smoke detectors, heat detectors, etc) into a single addressable point on the Simplex panel. Likewise, an old Edwards pull station could be turned into a single addressable point by adding a mini-module to the back box, but you can't do the same for a conventional Edwards smoke detector.
What you will not see are addressable Edwards devices active on a Simplex panel. All the big boys have proprietary protocols for their addressable panels.