The upside down pentagram star pointing downward essentially means the four elements of nature (air, earth, fire, water) oriented away from spirituality (ether) and toward materiality without spirituality.
The upside down cross is actually the symbol of Peter, the student of Jesus. Early Church tradition stated that the Romans crucified Peter upside down.
The double-cross over infinity is the chemical symbol for sulfur. Any reuse of the sulfur symbol is idiosyncratic and anecdotal, such as for the socalled Leviathan Cross or Cross of the Satan.