3 weeks researching..nothing on these 3 please help1

I have spent entire days trying to find out something...anything...about these 3 pieces. They come from an estate we inherited. Many items date back to the late 1800s. I would so much appreciate any help you could give this very tired researcher.
The first one looks like Samuel Clemens but no signature


The second one is marked 1870 in pencil on the back. The person who owned it was overseas quite a bit so it might have come from there.

I have researched this signature until I am blue in the face with no results...conjoined initials


And last but not least a little girl with hands crossed

This one is not oil or watercolor...it may just be an old print.

So those are the three monsters who have kept me awake until all hours. Thanks for any insight you could provide.