Putting my eBook online for free

Freelancer? Fiver?

The way to go its the email list so give it to people instead of their email .Then if you have experience in dating send them helpful emails and from time to time send promotiom with clickbank products with dating niche

Are you willing to be branded as the 'online dating guy'?

If you are there is a load of opportunity for promoting your book through traditional media.

It takes some planning and a few extra bits of content but would work.

Here's what I would do. Look on Google for various 'national days' that could be related to the book.

A quick search shows 22nd June is national kissing day.

Search for articles on this in various newspapers and magazines and see the type of thing they create.

Then you create content around kissing

The Perfect First Kiss
How she really wants to be kissed
You've been kissing all wrong

Contact the journalists who wrote the previous article and let them know who you are and how this might help the journalist.

Include a bio a note that you are an author and the book title and a link to your website.

I would then offer the ebook free (for getting on your list) but upsell a physical copy of the book.

Rinse and repeat all year.

That's very easy there are several agencies who are offering such services just Google the US Ghostwriting or Logocorps both are good in their working. They can do their work in a very reasonable amount.

What would be the difference between the content in your dating book and creating articles on your own to promote the site? I think you might run into the same problem in lack of traffic if your dating book content doesn't draw in traffic through SEO.

If you're able to get traffic from your dating site book content, then you could probably get traffic through original content, and monetize that traffic from the dating site book.

One of the ways to get quality content for a site is to turn some of your ebooks to posts. So, yes, it's a good idea.
You can engage SEO experts to turn it to a SEO optimized content. You can find these experts in places like seoclerks, fiverr, freelancer, and so on.

Indubitably sounds like a good idea. All the ways which you consider, and which are directed at monetization worth doing anyway. If you think that something might go wrong, then nevermind.
Your content is quite in demand nowadays, because until there is a prosperous sphere of online dating, such ebooks will be in demand as well.
As for your questions, then if you want to do it - then do it, it's better to try once, rather than regret in future that you haven't done it. As for the second questions, then if it will be pretty difficult to you to find a good web designer or a human who will build a SEO-optimized website, then you can apply to special platforms, which are full of such geeks.
Freelancing platforms, special forums of web designing, where are dozens of people who will be ready to help you for a wage.