Ginge
1. Sorted
2. Yes remove the red plastic rubbish above the kidney box.
3. You can buy goodridge fittings (adaptor and hose tail), to fit return into the sump plug hole (unscrew return pipe to drain oil).
4. Sorted
This is exactly how i fitted the breather to my old 3dr.

Breather normally bolted to bulkhead plastic stuff next to battery.
Mirror image tanks are coslty IMHO.

Dave