1) I assume you're using Slic3r as your slicing software? I found Cura does better at the top layer fill. Regardless, have you calibrated your extruder to make sure you're extruding the amount of filament that you should be?
2) Just select something other than 10 mm movement steps on the LCD. The Marlin software is set up to NOT allow Z-movement at the 10-mm increment. If you go to 1mm or 0.1mm, the Z-axis will show up as something you can select.
3) If you're printing from host software like Repetier-Host, you can get an idea of how much time is remaining. I don't think you have a way to see that on the LCD display.