You shouldn't worry about specifying the logo everytime, if for some reason it uses the default place holder you can just update the template without having to go back into the wizard. We have some info on this in the archived documentation section of the SiteAssist support page, here is a link:
In the archived documentation is the built in help as well as the modifying tutorials for editing the site after the fact. As for blog support this is not a feature of SiteAssist, any blog you wanted to add to your site would be a custom endeavor. If you have blog software that can integrate natively you could create a new set of pages to accommodate the blog but there is no automated incorporation.