I just worked out that F series mx13 diff and brakes into ae86 handbrake cables are ae86 S series. They fit perfect.
Also, from my current experience, there are numerous other things you can do to reco the mx13 drum system with other parts. Japlish told me that ra65 drums could be made to fit, and with a small step machined in them they fit perfectly to the older style backing plate.
Japlish also told me to use ae86 wheel cylinders to correct the hydraulic system, and that seems to be perfect too.
I bought shoes for an mx13 so thats original fit.
The rest are just the stock mechanical parts. Just clean and refit, and remember to grease where necessary.
All confirmed as accurate on my car, so peace.