It was mentioned to me by a friend of mine that maybe adding some soil to even the plane out wouldn't harm the tree due to the fact that I would only be adding soil to approx. 1/4th of the root system?

thanks for the info, but what I was planning to do was use my garage and keep the plants right next to the door to the outside(which will be open) to the outside A. for good circulation (I will also use a negative ion blower blowing on them slightly). So it will definitely feel the chill of sacramentos winter and get the required chill hours. So when you say defoliate the plant, does that mean I take off all leaves? or which ones would I leav? thanks

Sweet cherry often does this, and is almost certainly what your trees are. It is naturalized in this region, even crosses with the genuinely native bitter cherry (to produce Puget cherry). Raise the level of the lawn to (just) cover the roots, or take the trees out. Cutting off and pulling up the roots can't be counted on to not be detrimental.

thanks for the info! I so wanted a tree there and to know the roots won't cause major problems down the road is welcome news. My lawn is a big empty canvas right now and I'm so excited to get digging! Now to figure out what perennials to group with the tree!? Any suggestions? Its a south facing lawn with plenty of sun.