"I found the cold-pressed sunflower oil and coconut oil at herbal medicine, but the vendor told me that usually is used for hair or skin. The label says "coconut oil, cocus nucifera seed, cold pressed. Vegetable oil coconut. . I do not know if it is the right one for oil pulling."
Yes. Both sunflower oil and coconut oil are good for oil pulling. They can also be used on hair and skin although coconut oil is best for topical use.
"A curiosity. After 20 min what you usually do ? After 20 mins I wash my mouth with warm water, then brush my teeth and then rinse with a mouthwash aloe vera. Is it good ? Tell me how you do."
Your routine sounds great. I usually rinse with salt water after OPing. I don't always brush. It's a personal choice. Do what feels right to you. You are doing fine.
"I have a little afraid to go back using the oil pulling because a dentist told me that I have 5 small cavities, and I fear that during the process of oil pulling the cariogenic bacteria can infect healthy teeth. Is it possibile ?"
No. In fact, research has shown that oil pulling helps prevent cavities. As your cavities are small, it is possible they could harden and seal over. Go for it!