Is there a way to make a text box a required item to be filled out?

You have default values set, so they wouldn't have to change them to satisfy the required validation. Maybe try this:

<input name="eCart1_5_Name_Add" type="text" required="required" placeholder="First and Last Name" />
<input name="eCart1_5_Grand_Add" type="text" required="required" placeholder="Grand" />
<input name="eCart1_5_PupTentName_Add" type="text" required="required" placeholder="Pup Tent Name" />
<input name="eCart1_5_Description_Add" type="text" required="required" placeholder="VFW LM Number" />
<input name="eCart1_5_Title_Add" type="text" required="required" placeholder="Date of Birth" />
<input name="eCart1_5_CootieNumber_Add" type="text" required="required" placeholder="Annual Card Number" />