Mithraism was indeed a christ cult. The cult of the christ existed before Jesus and the earliest christian literature of the first and second century never mentions him and only uses the term "the lord". Mithra was clearly a god-man figure and saviour as was Jesus. He was shown as a handsome beardless youth wearing a Phrygian cap, depicted with a lamb around his shoulders and known as "The good shepherd". He was associated with the act of killing bulls for the redemptive value of their blood. The rituals and beliefs of Mithraism were critical in developing synchretic Roman Christianity since the religion had great influence in Rome especially in the important quarter of the military. Much "christian doctrine" came from this source including the Papacy and sacrificial death of the christ Mithra and the symbolic bread and wine as well as heaven and hell and Biblical eschatology.The trope of the god-man saviour was a well established expectation among temple worshippers with a pedigree going back many centuries before Jesus.
Orphism too has many resonances with the dying and rising God Dyonisus, another christ figure. Orpheus himself like Jesus going down to Hades for three days and arising again.
It is very popular to dismiss the parallels of the ancient christs because primarily it is uncomfortable information at least as far as traditional Christianity views it. Secondly there is little remaining literature and much of the connecting information has been gleaned through sculptural artefacts and yet a convincing path of ancient belief can be deduced including from the written Classical sources which promote the idea of the saviour, born of a virgin whose life was sacrificed at Easter to redeem believing mankind.