Although Catholic, I do not think you understand the Cathoic teaching on the subject. The Catholic church is monotheistic. The Catholic Church does not worship Saints or even believe that the Saints are themselves acting from heaven.
A novena (from the Latin for nine each) is a devotion in which nine days are set apart for prayer to God, Our Lady, or a particular Saint for a certain intention (a person or object for which prayer or Mass is offered). The first novena was the nine-day period from the Ascension of Our Lord till the Descent of the Holy Spirit, during which time the Apostles waited in Jerusalem for the "promise of [the] Father" (Lk 24:49). A novena concentrates our attention, increases our zeal, and strengthens our faith, that God will grant our petitions according to His will.
Catholics pray to Saints not as if they were praying to God, but to ask the Saints to add their powerful prayers to our own. It's not much different from asking friends to pray for you, except these friends are in heaven, see God, and are very close to Him.
Catholics have a Saint associated with categories into which most intentions fit (for lost things, recovery from illness, childbirth, students, policemen, etc.) because these particular Saints had something in their own lives that may make them sympathetic to our request. Over a period of time, when numerous people seem to benefit from asking a certain Saint for the same thing, that helps to solidify the association of the Saint with that particular intention.
Catholics believe that we are obliged to pray for each other, not only in this world, but in the next. Christians on reaching heaven don't forget the needs of those they have left behind. Otherwise, they would be less charitable in heaven than they were on earth. They know our needs and our prayers, because God reveals to them what they need to know to do us good. Praying to a Saint is not the same thing as praying to God. It is not worship, but asking someone close to God to intercede for us.
As to the foundation of the Catholic belief, the Bible directs us to invoke those in heaven and ask them to pray with us. Thus in Psalm 103, we pray, "Bless the Lord, O you his angels, you mighty ones who do his word, hearkening to the voice of his word! Bless the Lord, all his hosts, his ministers that do his will!" (Ps. 103:20-21). And in Psalm 148 we pray, "Praise the Lord! Praise the Lord from the heavens, praise him in the heights! Praise him, all his angels, praise him, all his host!" (Ps. 148:1-2)
Not only do those in heaven pray with us, they also pray for us. In Revelation, John sees that "the twenty-four elders [the leaders of the people of God in heaven] fell down before the Lamb, each holding a harp, and with golden bowls full of incense, which are the prayers of the saints" (Rev. 5:8). Thus the saints in heaven offer to God the prayers of the saints on earth.
Angels do the same thing: "[An] angel came and stood at the altar [in heaven] with a golden censer; and he was given much incense to mingle with the prayers of all the saints upon the golden altar before the throne; and the smoke of the incense rose with the prayers of the saints from the hand of the angel before God" (Rev. 8:3-4).
Jesus himself warned us not to mess with small children because their guardian angels have guaranteed intercessory access to the Father: "See that you do not despise one of these little ones; for I tell you that in heaven their angels always see the face of my Father who is in heaven." (Matt. 18:10).
Because he is the only God-man, Jesus is the only Mediator between man and God (1 Tim. 2:5), but this in no way means we cannot or should not ask our fellow Christians to pray with us and for us (1 Tim. 2:1-4), including those Christians in heaven, who have already had their sanctification completed, for "[t]he prayer of a righteous man has great power in its effects" (Jas. 5:16).
I am aware of the Catholic Doctrine but also aware of it's contradictions. I do not feel the need to pray to a saint when a prayer to an omnipotent God is an option. If you have any questions, please look up the definition of "omnipotent".