The CRLs say that a heavy black fabric is used for the for the cape and capelet (I personally would recommend a wool or wool blend). For their pattern, I would look at the patterns for medieval costumes (check joann's or similar fabric store) and then modify from there. From the description of the hood it almost sounds like an infinity hood or something similar so look at those as well.
Hopefully this helps...and If you haven't yet, I highly recommend checking out the CRL for Revan:
https://databank.501st.com/databank/Costuming:SL_revan
Another good reference for you would be the WIP area for Revan costumes, found here:
https://www.theflagshipeclipse.com/forums/index.php?/forum/80-darth-revan/