The website looks quite good, the web designer may want to consider formatting the text on the composer pages a bit differently though. Something a bit tidier?
1. It's reasonable. Just remember that less is more. And as far as newsletters are concerned, as I am sure you will know, try and find an even mix of image and text. Otherwise you'll just end up with a less than interesting jumble of words or a lot of nice pictures with what can appear like a lacking of content.
2. My advice would be to get a copy of Adobe Indesign (or a portable version). It's the best in the business for things like that. It allows you to set your page size, margins, text/ picture columns and once you figure out your typical layout it's easy then to just go in and edit it for the next edition etc... Allows for good consistency. Doing it in Photoshop would be a terrible idea.