1. You can cut and paste one of the guns in gamecore and then change the crosshair image to have zero alpha. That will make it disappear for you. There is no crosshair on/off at this time however.
2. You can adjust the model orientation of the gun you chose to edit (the bow) but it would require importing the X file into a 3D modeller, adjusting the pitch, then exporting it out again in a format that is still compatible with GameGuru. None of that super easy, but would create the effect you are after.
The good news is that the weapon system will eventually be externalized as a LUA script which means you will have total control of every aspect, and making these custom changes will be a natural and easier process than amending 3D models and textures.
PC SPECS: Windows 8.1 Pro 64-bit, Intel Core i7-5930K (PASSMARK:13645), NVIDIA Geforce GTX 980 GPU (PASSMARK:9762) , 32GB RAM