That stuff about the 5th book is nonsense. It was split simply because it would have been too long, not because it was ‘unfinished.’ And apparently Zach did skip most of A Feast for Crows, including the title. I, however, quite enjoyed it.
You can skip most of ‘Feast of Crows.’
I hope you’re ready for disappointment in book 5. Even after seven years, they managed to release an unfinished book to capitalize on the success of the show. (Then they blamed fans for being angry that they sold an unfinished book.)