How can I determine the artist full name and value for two old signed watercolor paintings?

Here is one resource to try and determine the first name if the artist has been listed.
There are some other venues out there that can help as well but I would start with that one as it has a pretty comprehensive listing. A subscription may be required to find out full information but it used to be that on every Friday the entire site was open to the public.
Either way it should help you with the name.

Let me know if that helps.

One way would be to call an auction house, some of them offer free/cheap evaluations of objects they could sell, with no obligation to actually sell them afterwards.

Check the Antique Roadshow schedule on PBS to see if they are going to be in your area. You will have to stand in line, but you will get an idea of their value, and if they are interesting pieces you may be asked to be part of one of the shows.