For the female lack of skin:
Open up the Materials file called YourCodename_Adult_F_YourCodename_Adult_F_mod0.bfmat, and look for the line
<param name="Texture0" type="texture">SeaLionCalifornia_Adult_F</param>
, and change SeaLionCalifornia_Adult_F to YourCodename_Adult_F. Check the YourCodename_Adult_M_YourCodename_Adult_M_mod0.bfmat and make sure the texture link is correct there too. Remember, you have to replace the bfmat codenames with something of similar length because they are referenced inside the BFB file.
Game crashing indicates a severe coding error, you must check that the arrangement of your folders and the location of your files is identical to how the folders are arranged within the x200_00.z2f file, because that demonstrates how the game finds data for it to read. If those files are incorrectly placed, then the game cannot find the information. You must also tripple check your animals/ai xml files to make sure your codename is correct and check that the Materials file references in the BFB files are the correct length and that in the BFM you have only replaced the codename in the lines:
<BFM modelname="entities\units\animals\SeaLionCalifornia\SeaLionCalifornia_Adult_F.nif">
<Graph name="SeaLionCalifornia_Adult_F" version="1">