I use a custom water based type mix applied over a lacquer gloss coat.
I probably fill that container you see next to the ink with 1/3 ink and 2/3 water with a drop ir two of dish soap added to break that surface tension. Hobby Lobby carries several different colors of this type of non-waterproof ink. I can do the entire craft and let it completely dry and remove it using a slightly dampened q-tip or a small folded square of tissue. I have washed at least 5 builds using the batch in the smaller container and its not even half empty. The bottle of ink runs less than 3 bucks at Hobby Lobby and with a 40% off coupon even less than that!!
On armor, I use Winsor and Newton oils like everyone else and usually apply them over an acrylic base.