Who controls?i

I was recently at a Seminar on Irrevocable Trusts, and I would like to know if I am correct in my reading of what the lawyer said. He said there are 4 important aspects. One, is the Grantor, Two ,are the Trustees. Three ,are the Beneficiaries. And the fourth, should be someone you trust completely, because that person is the only one who can manage the Trust. I do not recall that persons designation. Am I correct in assuming that my wife and I can be both Grantors & Trustees? Also, regarding Medicaid,my understanding is that if I, or my wife need to go into a nursing home, our House is not subject to "Look Back" of 5 years. Thank you in advance gor your help.