No they believe Jesus is a product of intercourse between God and Mary and that he lived a perfect life and thus earned his Godhood early and is one of 3 separate gods just for this planet.
As to your second question..”How many mainline or even evangelical Protestants don’t believe that Jesus Christ is the Incarnate Second Person of the Trinity?”
I am sure there are some individuals who don’t believe that but it is NOT institutional (as the Mormon doctrine is) and if they don’t believe that, they are not Christians regardless if they go to church or not.
Re: post 23
Amen.
Thank you for your clear explainations and speaking forth the truth.