Hi Marco,
I am sorry for the delay of this reply.
Regarding the feed import, this feature do not guarantee the layout of the content will be migrated 100% accurate due to how complicity of the layout structure ( html doms ) was built. Thus, after the post imported via the feed importer, you might need to do some cleaning task on the imported posts
Or, in when you create the feed item from the feed importer manager, you can disable the fetch the full content so that the importer only fetch the 'header' section from the page. This way, you will have less issue with the layout of the imported items
As for the social sharing issue, I tried to share one of the post to google+ and the sharing is working correctly. Please see below link for the images.
http://screencast.com/t/60fRRP5qH
http://screencast.com/t/XdVKfq4r
I also tried to share to google+ via the 'sharethis' feature and it working fine too.
Please see
http://screencast.com/t/UsydyuJK
Maybe you can capture a screenshot to us so that we can see the issues from your end?
Please advise.
Hope this help and have a nice day