When you're looking through the lists of databases, examine the scope of each database and be sure that it broadly meets the scope of the project (US, late 19th and/or early 20th century) before putting in search time on it. Many of these databases just won't be worth your time.
When you use the library catalogs, don't just search for their suffragist. You should also search more generally to get to books on black/African American women's suffrage. When you're pulling a book you found in the library catalog off the library shelf, look at the books around it. Books in academic libraries are shelves by subject area, so you can find other books on the same subject nearby.
Carefully document each source that your group finds about your suffragist. Whenever possible, place a link or PDF of the source you have found in your group's Google Drive research folder. Record all bibliographic information for each source you locate on your group's bibliography document in your research folder. Also include a short summary of the source and where you found it.