Well from what I have read you noticed that using "<link rel="canonical" href="link to our g+ page"> was a bad idea and have removed these entries which is a good thing. You should now do the following:
Link Canonical
Link Canonical is good and you should use it on every page but rather than the G Plus link with your own page so for example:
On the main page have: "<link rel="canonical" href="http://www.yourdomain.com/">
On deeper pages have: "<link rel="canonical" href="http://www.yourdomain.com/page-name/">
You should also ensure that no link canonical's to Google plus is active on any page, I'm sure you done this but double check to ensure this link is on no other pages as Google Cache will use the canonical link.
Google Cache Time
It's important to note that Google Cache is not real time compared to the actual search results, it can take days, weeks and even months to update the cache - this doesn't mean that your pages are not ranking. The idea of Google Cache has nothing to do with rankings but is to give Google search more features for the end users.
Google + Publisher Link
I'm sure your using something similar already but for the likes of other people with similar question you can use the Publisher link in the head of your pages like so:
<link href="https://plus.google.com/YourGoogleID-here" rel="publisher"/>
