Good morning, All soaps are ok, if there is no allergic reactions after use. Take care.

Yes you can use

If no colour change and no rash or anything no need to change otherwise we have to change

Yes, you can also use dove

yes can use Himalaya soap if the child is having no allergy due to it. tedibar / cetaphil / daffy / sebamed other options they are some of the good baby soap which is available in the market and you can go for any one of them but the important thing is that whenever you are using a brand of soap, after that if there is any skin reaction it is advisable to change the brand

No issues, if child has sensitive skin use a non fragranced milder soap