Based on de Montfort’s Mariology, which is really the Mariology of the Church, I would say ‘yes,’ any prayers which any particular saint receives is then transmitted to Mary who finally relays it to Christ.
If I am consecrated can I still pray a novena to a saint for a specific purpose? How do I keep my perspective on Mary for that? What would my prayers sound like, if different at all from how they are normally formed?
Yes. You can continue in pretty much all your prior devotions. What matters is recognizing Mary’s continuing role in securing our salvation, namely by acting as Mediatrix, serving as both Mother and model, and our own attempt to secure her virtues for ourselves. Even if you don’t consciously think about Mary while praying the novena to your patron saint, the dynamics of heaven would still function so that Mary would be the first to receive that prayer, polish it, then finally present it to the Lord as a spotless offering of love.
As far as your regular prayers are concerned, you might “glance” at Mary when praying to the Lord, but you need not change how you address him, what you say to him, etc. You might also end your prayer by saying, “I pray this by the intercession of Mary, Ever Virgin” etc.
And now that I am thinking about it, what about our patron saints? Where is their place in all this?
St. Gemma is one of my patron saints, though Mary is actually my confirmation saint. I still converse with Gemma occassionally. Gemma still provides a great example. Since we’re called to imitate the virtues of Mary, which are quite impeccable, imitating the saints, who themselves more closely model what is feasible, gives a great starting point for trying to imitate Mary.