Love Wanikani! Should I stop using Basic Kanji Book/Handwriting?

I would drop the handwriting for now, except maybe when you want to doodle or something. WaniKani is specifically designed to bypass the writing in order to speed up the comprehension process. (There’s a section in the FAQ about handwriting.) I think that looking up a stroke order guide would give you a good basis for knowing how to write any kanji you learn with this system.

As an aid, you could also use the Stroke Order Diagram script listed on the API masterpost. I don’t use it myself so I don’t know if it’s deprecated or not, but the Jisho stroke diagrams are very nice.