Anyway, Do the evangelists believe in all that? Do they believe that saints can show up to people and do what they did?
I assume you are referring to Evangelical Christians, who are adherents of the pan-denominational Protestant movement known as Evangelicalism. An evangelist, on the other hand, is a person who evangelizes.
Before I get into your question, let me just say that Evangelicals do not pray to saints. We do not pray to Mary, the Mother of God. We only pray to God the Father, God the Son, the Holy Spirit, or the Trinity together. We believe that the Holy Spirit helps us in our weakness and intercedes for us. We also believe that Christ is at the right hand of the Father interceding for us.
When it comes to visions and private revelation, different types of Evangelicals will give you different answers.
There are some Evangelicals who would tend to rule out all manner of modern day miracles and supernatural revelations. These tend to be cessationists. In their case, any supernatural vision of any kind would be suspect.
Other Evangelicals, such as Pentecostals and those inclined to more charismatic spirituality, will accept that supernatural visions and revelations continue to the present day. They would believe that an individual could receive a vision of Christ or angels or other spiritual beings. However, the individual would be cautioned to test such visions, because demons can take the form of angels of light and thereby attempt to deceive even the godly.
As a Pentecostal, I was always cautioned that seeing visions of deceased persons was most likely a demonic delusion. This is also the explanation for such phenomenon as ghosts. After death, a human spirit is either in the presence of God in some undefined intermediate state, or the human spirit is in hell.
Therefore, when Evangelicals do claim to receive visions, it will most likely be of Christ or angels.