Is dissent on minor questions answered in the Catholic Catechism considered sinful?

Catholics are not free to dissent from the Church's official teaching, while it is not only lawful, but obligatory to reject the teaching of a catechism, which is not part of official Church teaching (i.e. the Magisterium), if it contradicts something of greater weight, such as a Council or encyclical.

Is dissent on minor questions answered in the Catholic Catechism considered sinful?

It will depend on the circumstances and subject matter involved. Under normal circumstances the faithful may not dissent from the Church's official teaching.

The Catechism of the Catholic Church is an acceptable and accurate reference point for Catholics.

The only possible elements that could possibly dissent on would be on questions that have not been definitely defined. One may for example disagree with the Church's stance on capital punishment or whether purgatory is eternal or not.

You seem to be taking certain elements out of context. Catholics are obligated in conscience to honour their parents. For the Church, this is not a minor subject of dissent, but a grievous sin against one’s father and mother. Thou shalt honour thy Father and Mother! The Church can not contradict what God said to Moses. Dishonouring one's parents is part of the Decalogue and thus an obligation of consciousness to follow.

When Jesus who said, "I have come to set a man against his father" (Matthew 10:35), we must take into consideration the complete nuances of what inspired Jesus to talk this. He certainly did not mean we were exempt from honouring our mother and father.

Let us take capital punishment as an example:

Giving ammunition to these dissenters was a letter by then-Cardinal Joseph Ratzinger, sent to the US bishops in 2004. In his letter, “Worthiness to Receive Holy Communion,” the future pope wrote:

“Not all moral issues have the same moral weight as abortion and euthanasia. For example, if a Catholic were to be at odds with the Holy Father on the application of capital punishment or on the decision to wage war, he would not for that reason be considered unworthy to present himself to receive Holy Communion. While the Church exhorts civil authorities to seek peace, not war, and to exercise discretion and mercy in imposing punishment on criminals, it may still be permissible to take up arms to repel an aggressor or to have recourse to capital punishment. There may be a legitimate diversity of opinion even among Catholics about waging war and applying the death penalty, but not however with regard to abortion and euthanasia.”

This statement has been widely interpreted as permission from the Holy See to dissent from the Church’s official teaching on the death penalty, but is it really? Read in context, the statement is distinguishing between actions that are never permissible (abortion and euthanasia) and actions that—at the time—might be permissible if certain conditions were met (the death penalty and war). Because one must discern whether the conditions whereby it is permissible to go to war or to apply capital punishment are met, the Holy Father and an individual Catholic might reach different conclusions in good conscience. - Is Catholic teaching against the death penalty optional?

You'll get very different answers from the traditionalist parts of the Catholic church compared to the progressive parts. Traditionalists tend to believe in stronger guidance by the Spirit in preventing the Church from erring, while progressives tend to argue that the church's leadership is not always open to the guidance of the Spirit (sometimes even when they think they are).

For a specific example that shows both sides of the question, I recommend looking into the Pontifical Commission on Birth Control. The majority (including several cardinals) voted that modern contraceptives are not inherently immoral but should be considered extensions of contraceptives already endorsed by the church. Some members dissented, arguing that the Spirit would not have allowed such error to occur (especially when the Protestants had not errored). For reference, Paul VI sided with the traditionalist minority, while (according to Gallup in 2012) 82% of American Catholics consider birth control morally acceptable.

This isn't really an answer per se, but I hope it can help you further engage with and explore this question.

The prologue of the Catechism is correct, in that it serves as a reference. It is meant to be used as a tool for pastors to catechize their flocks. Your priest (or deacon, or an educated catechetical lay minister with the proper training to whom your priest has delegated this responsibility) should be offering catechesis to the parish at all levels of formation, but especially for adults, giving them the tools to teach their children. The catechism is supposed to be used by the catechist towards this end.

As to having contrary opinions to what the catechism says, it will depend on the category of the teaching, whether it is authoritative or not. Not everything in the Catechism is an authoritative teaching, and you will need to go find that teaching elsewhere in the documents of the Church in order to determine whether it is authoritative, infallible, etc.