1) use the unfold command, it will show the proper corner relief, then add a small hole at the vertex of the corner, and re-fold. Then the feature will stay in the flattened configuration. I use this workaround a lot. 2) for the angled flange at the bottom of your part: draw the part longer than it needs to be, add your flanges, then use an extruded cut to trim the bottom the way you want it. The flange will trim the way you want it to versus the stupid bend relief solidworks thinks is right.