I believe in two salvations, one heavenly for the church and the other earthly for the rest of mankind, however I don't limit heaven to 144,000, believing the Great Company is also a heavenly class. One serves on the throne and Kings and priest with Jesus, the others serves before the throne as underpriest.
Every man, woman and child who ever lived will be resurrected on earth, in which during the millennial reign of Jesus will learn what God did for us through his son Jesus, they'll grow to perfection and have the opportunity to prove their loyalty during the "little season" when Satan is let loose to deceive. At that point, mankind will be perfect and stand on their own merit. Sinning cannot be blamed on adamic death as Jesus paid that price, they will die for their own sins.
RR