You are correct that the green discoloration of the nails is usually a bacterial problem called pseudomonas. It is a common bacterium that lives in water, especially hot water. Pseudomonas is often a secondary bacterial infection, which means it infects a nail that is already damaged, perhaps by psoriasis or onycholysis. Pseudomonas will often spontaneously disappear when the underlying nail problem is cleared up. There are several home remedies that will treat pseudomonas very effectively. The simplest treatment is to use diluted white vinegar soaks (1 part vinegar to 2-4 parts water) for several weeks. You can store the solution in a dropper bottle and apply one drop under the nail twice a day. To remove the discoloration, the nails can be rinsed in a diluted bleach solution (1 part bleach to 4 parts water) once or twice, but not for prolonged periods. If these simple remedies fail, a doctor can prescribe antibiotics for resistant cases. — Dr. Rich
Bacterial infections account for almost all green discolorations on the surface of the nail plate (under the enhancement). That they are mold and mildew is a myth, and fingernail fungal infections are also pretty rare. The vast majority of green bacterial infections are caused by improper preparation and/or application. Improperly cleaning the nail leaves it contaminated with bacteria that can grow after the enhancement is applied. Improper application can lead to lifting, which can allow bacteria to get under the area where the product has separated. The problems you listed cannot cause these infections. — Doug Schoon