I apologize, I went off topic. To be fair though, I just followed the trail you started with talking about tearing out pages of the Bible, and Elin posting NT verses that don't need to be torn out because her interpretation of them agrees with her doctrine. So, on to your OP question (if I've grabbed the right one):
IF the two commandments fulfill all other commandments of Christ, do they also fulfill all the commandments of Paul, James and Peter?
I don't agree with the proposal that the two greatest commands fulfill all the other commands of the Messiah. Many others have already said what I'm about to say: they are principle or summary commands. The Messiah said they are the most important two, not the only ones. They don't replace the others. If you prioritize these things, you'll have the right heart to desire God's will to live how He has revealed through His commands, the prophets, the Messiah's life, and the writing of the apostles (properly understood). So yes, I suggest doing what the Messiah commands. He's our Master. And look at His actions since actions can speak louder than words. None of this makes you a legalist. You're not doing it to merit salvation but because you are saved and love God with all your heart, mind, and strength, and your neighbor as yourself.
It sounds like you are trying to test something you picked up on this board. Good for you. Paul says to test doctrine presented to us. So, to answer your question, we should be keeping the teachings of the Messiah and His disciples/apostles. The two greatest commands don't replace what the disciples teach. These teachings should be equal and in agreement if the disciples are truly teaching after the manner of the Father and Son. It's their job to match the Father and Son, not the other way around.
About whoever told you to ignore all Christ's command except the two most important ones... maybe you misunderstood that person? Or maybe not, since there are many people who feel that much of what the Messiah said has no practical application to believers today. When He makes obvious pro-Law statements, they say those were meant for a dead works people living under the Law. If he seemingly makes statements that agree with their personal doctrine, then they selectively say those apply to us today. Convenient system. Farley's "The Naked Gospel" makes this same exact argument. We end up becoming the authors of our own faith when this is our interpretive method.
Keep all your Bible pages, please.