1. Not sure, I think it needs some script changes. I think she uses a sword even when you have the only one you have equipped.
3. RIMs -> Modules -> 711KOR_s.rim -> npc_v_malak.utc
Open that utc, press the inventory button. If you hover over the hand slot with the green outline then you see he has a g_w_lghtsbr02 there, that's a red saber. Now you can drag another saber from the list of items on the left to that hand slot to change things. Most lightsabers are only called "Lightsaber" there, so it's a matter of trying if you get the one you want. A blue saber is g_w_lghtsbr01, the one below the "Dark Jedi Lightsaber".
An easy way to check those "codes" is to check in a list of cheatcodes like https://www.gamefaqs...th-lords/cheats
After changing the inventory you can save the utc to your override folder to test your changes. You might need a save from before you went to that area for the 1st time, not sure in this case.
2. You can change the row for her evil look in appearance.2da with data from the row that's her normal look. You can do something similar as above with her p_kreia_evil001.utc in module 907MAL_s.rim, but I doubt it will affect the floating sabers.