Catholicism’s central truth, the Eucharist, The Mass, the authority of the Petrine Ministry to teach one truth, is directly antithetical to the beliefs of all other Christian religions. There aren’t many pathways to heaven. If so why proclaim one teaching and one truth? If Hinduism, Buddhism, Judaism, are all valid alternative paths to God, then the life and death of the Christ was superfluous.
The chief problems I have with your post center around those two underlined words. Are you saying that Hinduism, Buddhism and Judaism are "other Christian religions"? Are you saying that "all other Christian religions" claim that there are multiple pathways to heaven, or that they specifically teach that Hinduism, Buddhism, and Judaism are "valid alternate paths to God"?
How do you square the words of your own cardinals, to your post above?
Who, then, can be saved?
Catholics can be saved if they believe the Word of God as taught by the Church and if they obey the commandments.
Other Christians can be saved if they submit their lives to Christ and join the community where they think he wills to be found.
Jews can be saved if they look forward in hope to the Messiah and try to ascertain whether Gods promise has been fulfilled.
Adherents of other religions can be saved if, with the help of grace, they sincerely seek God and strive to do his will.
Even atheists can be saved if they worship God under some other name and place their lives at the service of truth and justice.
Gods saving grace, channeled through Christ the one Mediator, leaves no one unassisted. But that same grace brings obligations to all who receive it. They must not receive the grace of God in vain. Much will be demanded of those to whom much is given.
-- concluding paragraph (formatting mine), from the thread Who Can Be Saved?
article by Cardinal Avery Dulles