I've had new unglazed and slightly glazed porcelain tile (very thin grout lines) installed in 2 new bathrooms (new build and remodel). My General Contractor GC used a so-called "master tiler."

However (1) he used the wrong color grout for the tile (in the showers, on the bathroom floors, and on the tub surround; (2) he left a mess with lots of grout haze and dried chunks of grout all over the tile, the metal edges and surrounding areas: and (3) he used grout and not caulking in one bathroom where the tub meets the tile causing cracking even though I've never used that bathroom yet (only the plumber and shower door guys have stood in the new tub). (4) Also it seems the tile guy didn't mix the grout properly (not using enough water or too much or whatever) since the grout color looks different in different places,

He was supposed to use a white grout as specified but he used an almond color which makes the tile appear to have mildew stains. No one could believe the look of my brand new unused bathrooms!

Anyway, my GC wants his workers (not a professional tiler) to clean the tile, remove the grout and apply the proper color. His guy is using a kind of razor blade to remove the grout but he says he can't remove all of it (and it's taking him forever to do what he's doing).

So my questions are:

What is the proper way to remove grout to not damage the new tile or the new glass doors? Or is some minor tile damage inevitable?

Does all of the grout need to be removed since the color of the original grout will not blend in with the correct color grout?

How do you clean grout haze and chunks of grout off of tile without using powerful acids?

Is it possible to remediate this situation without removing the tile or should the whole thing be gutted and started from scratch to have this job done properly?

I think that's all of my questions for now.

I'd GREATLY appreciate any help you can offer! Thanks so much.