All four pics are of the same plane, the model does not come with wheel pants, flying off grass they are not an option anyway, they get full of sheep sh** and lock up the wheels, if you fly off pave then they would certainly enhance an already good looking ship.
As to making up the gap at the nose, a balsa spacer may be the way to go, but I will probably use some lightply to give it a bit more strength.
The Ailivators are very effective at slow speed they increase the manouverability out of proportion to normal, at high speed you can get the same effect by increasing the aileron movement only, but rolls are more axial, its the slow speed manouvres that butter my turnips, simple mod see earlier pics in this thread.
Mike