According to SDA can all pastors forgive sin, or just the original twelve apostles? I have a question relating to Matthew 18:18. I want to specifically ask the Seventh-day Adventist church about this.

It says:


  "I can assure you that when you speak judgment here on earth, it will
  be God's judgment. And when you promise forgiveness here on earth, it
  will be God's forgiveness." Matthew 18:18 ERV


Does this verse apply only to the twelve apostles that Jesus spoke at that time, or does it also apply to all pastors and ministers, that they can forgive sin, and/or does it also apply to churches today that whoever they "loose" from their churches would be "loosed" from heaven? So if a church today (let's suppose it's the one true church) excommunicate a member does that mean that that person is excommunicated in heaven?

Does Seventh-day Adventism vary from mainstream Christianity on this topic?
I'm not of the SDA church, but because you ask about SDA opinion specifically. I can tell you adventists cite Mt. 9:3 || Lk. 5:21 to demonstrate that the Catholic Church's claims to forgive sins constitutes "blasphemy":

Jesus. . said to the paralytic, ‘Take heart, son; your sins are forgiven.’ Then some of the scribes said to themselves, ‘This man is blaspheming.’ (Mt. 9:2-3)

Then the scribes and the Pharisees began to question, ‘Who is this who is speaking blasphemies? Who can forgive sins but God alone?’ (Lk. 5:21)