Anne,
start out with having a signature here on BP, link that to your website.
I will try to answer a few of your questions.
Domain forwarding will get the user to your ultimate site, but will not do anything for you in terms of SEO. I would have separate sites if the topics are too diverse. If the topics do not have any synergies and somebody that is coming to look for one thing is completely not interested in the rest then do different domains.
That is considered at "black hat" strategy. Google knows and sees what you are doing, they can read your HTML. In the worst case you will be banned. This is NOT a good strategy at all.
Search engine submittal is a waste of time. Google, Yahoo, MSN and you have 98% covered. This is unless you are in a niche market where a niche search engine exists.
Link exchange is not as important as it used to be. Two way links are better than no links but one way links are king.
Read a good SEO book, it will help you a great deal in understanding what people will do if you decide to hire out the SEO effort.