謝謝大家，看來大家的意見是不用set irrevocable trust. Wow, I was going to d

I was going to do that in the next couple months! Thank you so much for all the suggestions.  我再與financial planner 商討一下，will update you.  
one more question:  now my net worth let's say is 10 million (after tax money).  20 years later it will be 20million.  I guess it should still within the exemption amount.  But if I did not withdraw or sell the house, the pretax money will be 40 million, that will be more than the exemption.  Should I withdraw all and pay the tax and sell all the houses.  So the amount when I die, will be within the exemption?