Well, first, let’s be clear, number 841 of the Catechism is a direct quotation from paragraph 16 of Lumen Gentium, the Dogmatic Constitution on the Church. Many books have been written about it, and I’m sure many more will be. I’m not going to reargue the whole issue here, and frankly armchair theologians arguing things generally does more harm and spreads more error than anything else.
At any rate, the passage you’ve quoted says nothing about who will be saved. It says that the “plan of salvation” includes the Muslims, but isn’t that obvious? God’s plan for salvation was a plan for all mankind. Not all will be saved, but Christ did indeed die for the sins of all men – even those who reject him. The other part of the Catechism you bolded says that there are true and good things in other religions, and that we ought to acknowledge them. This is also obvious: if a religion says there is one God, who created the heavens and the earth, that’s a truth that it’s teaching. If it says murder and adultery are wrong, and tries to inculcate those values in its faithful, that’s a good thing.
The same religion also states that Christ is not devine and that he did not die for the sins of mankind. In fact they say that he was not crucified, it only appeared so and that Christians worship three gods. It also says that there is no original sin and that Christ was not neeeded for salvation, as each person has the ability to save himself. There is no Holy Spirit.
(Sura 4:171): “Believe in Allah and say not ‘Trinity.’ Cease! It is better for you! Allah is only One God. Far is it removed from his transcendent majesty that he should have a son.”
From the Koran, and yes I did not say the Holy Koran.

Sorry if I offended you
Koran (5:51) - “O you who believe! do not take the Jews and the Christians for friends; they are friends of each other; and whoever amongst you takes them for a friend, then surely he is one of them; surely Allah does not guide the unjust people.” What? You mean they are not supposed to be our friends?
Koran (5:80) - “You will see many of them befriending those who disbelieve; certainly evil is that which their souls have sent before for them, that Allah became displeased with them and in chastisement shall they abide.”
Koran (3:85) - “And whoever desires a religion other than Islam, it shall not be accepted from him, and in the hereafter he shall be one of the losers.”
On the whole, Islam is very clear in teaching that there is no equality between believers and unbelievers, and hence no basis for a relationship based on equality. Those who do not belief in Islam are intended to exist in subjugation to those who do, then spend eternity in Hell. This does not stop Muslims from acting friendly toward others, of course, but this does not mean that they are really friends…
Conversion by Muslims to other religions, is strictly forbidden and is termed apostasy. Muslim theology equates apostasy to treason, and in most interpretations of Sharia, Islamic Law, the penalty for apostasy is death
As far as murder being taught as being wrong, I think that is somewhat debatable as is most Islamic Law, which is based the the Koran . Ditto with adultery. It all depends on who is murdering and who is being murdered and who commits the adultery. Further, forensic evidence is considered inferior to eyewitness testimony and personal oaths. Thus, a Muslim could murder a non Muslim, swear that he di not do it and walk away scot free, irregardless of any actual physical evidence that might prove otherwise. Pretty cool huh?

.Of course if he kills a Muslim, he could have some difficulty if another Muslim saw it and testifies. A womans testimony is only half as valuable as a mans and the testimony of a non Muslim is excluded totally if that testimony is against a Muslim. So in our above murder example, a Christian witnesses the murder and testifies against the Muslim. No good, that testimony is rejected. A Muslim woman witnesses the same murder and testifies. The murderer says he did not do it, swears an oath that he did not do it and voila! Scot free again for the womans testimony is trumped by his oath and religion. In adultery for example. The husband accuses the wife of adultery. Remember, his testimony has more weight than hers automatically, so she is guilty. Just like that… She can be stoned. The man commits adultery. The woman testifies against him. He denies it and even goes so far as to swear an oath that he did not do it. Scot free again. Oh and just for good measure divorce is permitted and polygamy allowed.
In some Islamic countries, such as Saudi Arabia, it is illegal to practice the Christian faith. You cannot even wear anything that is obvious that shows you to be a Christian such as a crucifix. And whatever you do, don’t ever try to preach Christianity or you will be sorry.
Yep, it sure sounds lIke a good thing to me and something that we should all be proud to associate with.!

