Thanks Robin and dongvan03 for your advice. But I am still a newbie when it comes to testing and all this stuff about creating a sub-domain. Maybe I should just get another cheap domain and webhost and reproduced test pages on that website to test out each of those themes. On the other hand, I could use back that third website located at ICV where the initial crash first occurred since it is a simple one page website on a local government sponsored grant that is going to be terminated shortly and which I am no longer promoting.
I will carry out the plugin testings and come running back here again if I encounter problems along the way. But it will be great if anyone in here happened to use the same themes as me and can share their experiences.