Are there any resources available to help rewrite the code i.e. a wiki to support a fork?
no, but there is plenty of documentation in
zcash/doc at master · zcash/zcash · GitHub, Home · zcash/zcash Wiki · GitHub.
also check the first successful fork of zcash - GitHub - z-classic/zclassic: Zclassic is financial freedom. ZK-SNARKs, and no founder's fee. for further ideas
Thank you kindly, this is great!