I have been told that one of the requirements for Fieldwork II and III is to work on either two research proposals or a research project. Can my I use the same project to fulfill the requirement of my Fieldwork classes and the Honors seminar?

Yes, your paper for Fieldwork and the Honors seminar can (and in fact should) stem from the same project. However, for the Honors seminar, you will be required to take the project one step further. The instructor of the Honors seminar will discuss the various options with you, but these include submitting your project for presentation at a professional conference.