Beautification & Cosmetic Suregry

No

You must ask them if the color that they are applying leaves a mass on your hair. If this is the case, you must not use it. Also, you can apply any color except for black (or a color that looks like it).

Since it looks like black, this is not permissible.

No problem in going to a place where no non mehram sees you and getting it done by a lady providing you don’t expose any awrah.

Beside the fact that this is extravagance, it is not permissible for men to use such gold devices and carrying it on them

This is not permissible if non mahram men would see your face.

This is permissible if it is not harmful and if no non mahram men can see it.

Hair extensions are prohibited and Allah curses whoever does this. Kindly refer to the following link(s) https://www.assimalhakeem.net/shiek-is-it-permisible-to-tease-the-hair-to-give-it-volume-as-to-put-something-like-a-sponge-donut-in-the-hair-to-make-a-bun-in-the-lower-part-of-the-neck/

As long as after peeling it off only the color remains and not a layer that may prevent water, this is permissible.

You must repent to Allah and seek His forgiveness. You can dye it any other color that is not black, weird or would be considered imitating the Kufar.