Hi,
I went to Newfoundland this summer and had a wonderful time. Spotted several icebergs - according to the locals, they are lasting much longer this season. Consider following Iceberg Finder on twitter - there still seem to be plenty in Twilingate. I do not know about Avalon and Bonavista but this year you may be lucky.
When in St. John's, make sure not to miss the tasting at the Quidi Vidi brewery and have dinner at Bacalao. You won't be disappointed.