I just finished making my Reika. Hakuma are not that hard to make if you find a simple pattern. I opted out of making panels and pockets for mine since Reika does not look like she has those. I also used a gray body suit for mine. The costume can be seen here:
For the tattoos I used blue sharpie markers (the fabric or felt tip brushes are the best) and drew on all of the tattoos. Took a while but I love them! If you have a dress form that would be the best to put the suit on and then start drawing. I drew my main points first which were the dragon/snakes. Then added the rest. I used this pattern from an artist on Deviantart to create her tattoos!!!! It's the best!!!!!! Reika tattoo link
Good luck on your costume!!!!