B767 Captain reported multiple EICAS messages after take off and elected to make an air turn back and precautionary landing.

Narrative

On climb out from ZZZ we had multiple EICAS messages display for short duration and then extinguish. Many of these disappeared before I could note what they were; but the first one I remember seeing long enough to take note of was L IRS ON DC. (Our R IRS was already on deferral). This MSG went away and then later in the climb out (I think around 9;000 feet or shortly after) we received the MAIN CARGO FIRE EICAS Warning Message and unlike the other messages it did not extinguish its self. The fire bell did not sound.'We had suspicion this was a related erroneous message but do to the danger of onboard fire this message was treated seriously and we performed the QRH procedure for MAIN CARGO FIRE while also informing ATC of the situation; and the need to return to ZZZ using Captain's authority. We were still in close proximity to the ZZZ airport at this time.Throughout this time other EICAS MSG's presented themselves and then went away. One of these was APU Bottle 1 but it then extinguished itself. My First Officer stated he also observed APU FIRE pop up for a period of time but I do not remember seeing this particular message.My First Officer was the Pilot Flying and I had him continue to fly the airplane while I ran the checklist and radios; notified the two jump seaters of the situation and set us up for return to ZZZ Runway XXR. On Final Approach to [Runway] XXR the MAIN CARGO FIRE EICAS warning message went away and I informed ATC that the fire message went away.We were not overweight and my First Officer performed a normal landing. We stopped on the runway and waited while CFR performed a circle of the airplane. They said everything appeared normal and their thermal imaging equipment did not detect a fire. With the fire indication no longer present and checking the brake temperatures to be cool enough to taxi I chose to go ahead and taxi the airplane back to the gate. CFR followed us to the gate. Brake temperatures never got above 5 at the hottest and that was only on a couple brakes.'After block in and accomplishing the shutdown checklist I called dispatch and we also had a conference call with the duty pilot. Then we had a lengthy discussion with ZZZ Maintenance on the flights events and completed the aircraft logbook.During the course of the flight we remained with ZZZ controllers who did an excellent job vectoring us back around promptly; giving us the weather (which was well above cat 1 mins); and informing the company of our return.It is obvious now that a fire did not actually occur and this was an erroneous indication related to the other EICAS anomalies that were occurring on the aircraft. While most of the messages did not remain displayed for a long period of time the Main Cargo Fire warning message remained on until final. As directed by the checklist an immediate return (land at nearest suitable airport) was the safest and most prudent action.