I addressed part of this in another email. If the trees remain, the best shade tolerant grasses are fine fescues. Growing in the shade they should not be over fertilized or over watered. Surface roots are normal and could be lightly covered to make mowing easier. Some shade tolerant ground covers include: Hosta, Ajuga, columbine, bleeding hearts, ferns, wild ginger, sweet woodrug, turtlehead. At somepoint when the sunlight is so low, mulch, statuary, a collection of boulders done tastefully set in the mulch area can provide visual interest.