Glad you have been able to install it, I have a 0.2.2-alpha4 version which includes the sidebar widgets and additional plugins eg Lightbox, simply not gotten around to releasing via SourceForge.
Now to answer your questions…
1 - the template’s can easily be edited via the ‘presentation’ panel if you make the folder and files writeable. However if you look into the ‘default’ folder you’ll see a folder called ‘header-images’ if you place your header images in here (use the current as a size guide) you’ll get a new image on each releoad of the page.
2 - the widgets plugin works in the latest version which I’ll send to you before I release it (please remember this is BETA) and there is NO upgrade path, so you’ll need to export your current blog entries.
As for a thread for SkratchPad there is nothing here as it’s still a very small project if you want to follow the progress you’d be better to get a SourceForge account and ‘monitor’ the project you can then get an e-mail every time I release a new version.
If you PM me your e-mail I’ll get you this copy sent over (approx 3.5Mb)
As for enabling comments you do that via the admin panel ‘options’