I can answer a few of your questions.
Yes, you can use OO.o and eliminate Word (as well as the other components of Office); many of us have done so.
If you want to send an OO.o file to someone else, it is best to first either save it as a Word or as a PDF file, and send one of those files since these applications are ubiquitous. OO.o will allow you to pull up the document and save it as either of these two.
The wordpad interference may be caused by an improper file assocation. See this topic, which although discussion picture file type associations, will apply:http://www.bleepingcomputer.com/forums/t/40808/how-to-change-which-application-opens-your-pictures/
Hope this helps,