Hi, SemperReformada,
Let me try my hand at resonding to your post. I am taking a bit of a Lenten Break - except for Sunday…

So, I will try and be as thorough as possible.
PR,
Do you believe the scriptures contain all that one needs to be saved? In other words do you believe in the material sufficiency of scripture?
Actually, no, I do not! Let me tell you why: Scripture contains a wealth of material - like all the parts to a Swiss watch - but, the ‘how to’ or the ‘directions’ are not there. Here are a couple of examples. Just ‘how do you’:
Baptize someone - the Catholic Church requires a specific way to do this, yet Protestants are not only in disagreement about if it is even necessary - their forms are all over the place.
Have a Priesthood - Christ told the Apostles to “Do this in rememberance of Me” and thus established His Apostles to follow His Command and consecrate common bread and wine into His Body, Blood, Human Soul and Divinity. Christ also delegated to these men the power of God to forgive sin - and the Catholic Church has a very special way for men to become priests and fulfill Christ’s commands. Protestants, converesly, dispute the Real Presence and deny the need for priests and have no sacramental Confession.
Resolve differences - In Acts we see where the Judiazers created the first theological crisis for the Early Catholic Church. It was ultimately resolved by Peter declaring, under the direction of the Holy Spirit, that circumcision was no longer a requirement. Even the briefist reading of the OT would give a person the confidence that circumcision was required by God as a symbol of the Covenant - from Abraham forward, this practice was not to vary - even if the 8th day fell on the Sabbath! Yet, here we have the break between the OT and the NT - coming from Peter without referencing Scripture. It would appear that if Protestants disagree, they separate from whatever was their ‘original’ organization and found another - and that is how we ultimately get to 30,000+ groups all claiming to be right with conflicting doctrines.
As you already know there is no list of the “essentials” and there is no way to answer your question adequately. But, what is the Catholic alternative for this? Is there a list of infallible declarations? I don’t think there is.
Actually, there is - and you identified it in your next paragraph: the Catechism of the Catholic Church (CCC). Everything you need to know is right there. Please recall in John where Christ told the Apostles that He had much to tell them but they could not bear it now (John 16:12) and then John concludes his Gospel by telling us that not everything Christ did is recorded in these pages. But, do not feel abandoned (Christ promised He would not abandon us… John 14:18) for He gave us the Church He founded on Peter (Matt 16:18).
Here is a link to the CCC:
scborromeo.org/ccc.htm Seriously, if you have any question about what the Church’s teaching is on a particular subject - it is answered.
Now, as far as directing someone to a so-called list of Catholic essentials, we could start off with the Apostles Creed (
newadvent.org/cathen/01629a.htm) - but, please note, Christ did not provide the Catholic Church with a Policy and Procedure Manual - so we see some development in doctrine that is actually reduced to writing and established as official Catholic Teaching - not the difference between the Apolstles Creed and the Nicene Creed (
newadvent.org/cathen/11049a.htm )
Obviously there is more to following Christ than professing He is God (the devils in Hell do that much (James 3:6)) or that saying, “Lord! Lord” - or even working ‘mighty deeds’ will accomplish anything positive for one’s immortal soul (Matt 7:22) And, that ‘more’ is spelled out in the CCC. The areas of distinction between Catholic doctrine and the various beliefs of Protestantism can fill volumes - the take home message, however, is really straight forward: looking for a ‘list of essentials’ is a fool’s errand - knowing what makes up the Catholic Faith is something that takes time and study. I really think the CCC will give you the answers you seek.
God bless