Yes, enter the value on the date of death for cost or other basis.
Yes, enter the broker's commission as a selling expense on the less common adjustments screen, provided that the commission is not already subtracted from the proceeds shown on the 1099-S.
Preparing the house for sale cannot be claimed as a selling expense or other adjustment.
I would not enter any adjustments other than the broker's commission. The adjustments "for a reason not already covered" are likely to raise questions.
