A lesser drop might be more convenient but what if they eventually want twin beds again. Might ask gg's and their mom what their opinions are!! Unless these are a surprise!!
Another thought might be sleeping bags made with a quilted cover. When my son was little and wanted a loft bed we used a sleeping bag for his bed. I simply covered the mattress with a quilted fitted "sheet" and when he made his bed he just spread out the sleeping bag. No overhang and the quilted "sheet" if showed was attractive. Just an idea.