Also, I've noticed that when I export from Excel to the gdb, it doesn't include numerous records with underscores, but it does from a CSV. Am I doing something wrong?
What has underscores? The field names or the data within the columns? You should be able to:
Open arc map and using the add data button, add your excel workbook to the map
Right click on it and open it to view the contents
While in the table window, right click on the table options button and select export; point your output to whatever gdb you want
I try to stay away from csv's if I can.
You can do a similar process in arc catalog; navigate to you excel workbook and open the page you want and export it to a gdg. Or in arc catalog, navigate to your gdb, right click on it and select import table.
That should just about do it....