The cleaning routine must be carried out first, as this will clearly identify all mortar which is in need of repair. Repointing is essential !
AS facade cleaners, we would recommend a blast cleaning routine, using soft abrasives such as calcium carbonate. This will be sufficient to also gently clean the surface without damage, but it may well be the case that the old brick was a dull colour originally.
Weather proofing the surface is possible, but always insist on a moisture vapour permeable coating which allows the surface to breathe.