Maybe I need to mention more info in my question. I'm from myanmar and we've got a lot of sunshine and a lot of rain too during moonsoon season. We're not doing new buildings, just repairing a historic building built around 1900. This building is basically abandoned for decades, and it's quite big. A lot of bricks need to be replaced, but in some areas we intend to use lime mortar with brick dust to imitate a brick rather than raking out and replacing with a new one. But we're not achieving the same color as the original brick but when we add laterite powder to lime mortar, color is satisfactory. Our only concern is that we don't want the repaired areas faded away after three or four years.

If you are repairing brickwork identifying the causes of stains will help:
Brick Stains: Identification & Prevention

Most staining is caused by improper cleaning not the mortar, lime run for instance is not actually caused by the lime. The only material you really have to worry about with lime is manganese, laterite is rich in manganese, but this is only an issue if it is fired first which mobilizes the manganese, acid washing further mobilizes it, the lime actually causes it to precipitate, if it is unfired however it is already stable and mixing it with the lime will not matter.

The fading, additionally, will be uneven where water, or sunlight, is unevenly distributed over a large surface. As for your "ochre" pigment, I suspect that it's not a powder ground from just straight up iron-oxide, but some kind of liquid ochre-colored emulsion specially formulated for mixture with concrete. Get an assurance that your boss's "earth color" dye, or additive, is lightfast, at a minimum.