Twitterfeed & Feedlr are two third party services that can automatically update your Twitter with your new blog posts. They support both RSS & Atom feeds. So whether you use WordPress or Blogger or whatever, you would have no problem with that.
If you use Blogger blog, you may feel this. You are looking to add a favicon but there is no facility to do it. Here iconj.com comes very handy. They will host your favicon for free & you will get a direct link to it from your blog. All you have to do is to add a few lines of HTML code in between <HEAD> </HEAD> tags. Besides, it includes both the codes so that favicon gets compatible with old & new browsers. If you are using free hosting for your site or WordPress blog, then Hotlinking might be disabled on your server. You can use this free service in that case too.