Adding html subsites to Drupal 7 installation
I don't know anything about BlueHost or their tools, but the normal way to do that would be along the lines of:


Make a folder to house your HTML-only site
Put your site files in the folder
Set your webserver (Apache/Nginx/IIS) to direct requests for subsite.mysite.com to that new folder


Drupal is not involved in any way, shape or form.

So the answer is likely that there will be no problems, however I suggest asking this question of BlueHost as it really has nothing to do with Drupal.