Welcome to the forum.

As long as you are going to use a paid adult host, you can post any kind of content that is legal on your new blog (unless it is something illegal like CP or it is something really extreme), but you will be fine with the lesbian porn, gay porn and cams or even BDSM content.

You do not have to put any warning messages, unless you are going to use the free host like BlogSpot, because they require to warn visitors about the adult content. If you are going to use the paid hosting, you do not have to put any warning messages on your blog.

If you are just starting out, then you do not really need much of knowledge about the SEO yet. Just make sure that you create a unique site with good content and you do not copy posts from other sites. If you write posts yourself, your blog should do well on the search engine sites like Google or Yahoo.

There are many ways to get traffic for an adult blog. You can try to get some organic traffic from the Google by working on the SEO, but it will take time before seeing any significant results, but it is the most rewarding kind of traffic. You can use social media sites like Twitter or Tumblr or you can exchange traffic with other sites and these are only few ways to get new visitors.

You will find more information on how to get traffic for adult blog here:

How To Get Free Traffic To Your Adult Website

Also make sure to check out this page:

Start Here

You will need a blog before signing up for affiliate programs unless you have social media traffic or something else, but it is best to have a website beforehand.

Blogs are better than white labels, because white labels hardly get any traffic from Google because they are just a copy of the original site.