I am also using Kraken.io to compress images - but I don't think it is the problem as the Images I upload to the wysiwyg field of the same page are fine.
Problem #1 - When I upload the image to the custom field in the backend of Toolset the image gets blurry.
I took a look at the page you sent and it looks fine to me, the images do not appear blurry. If you could provide a screenshot of the issue on your end that would be great.
Problem #2 - Toolset apends "-wpcf_300x427.jpg" to the end of the image
This is actually expected if you are displaying the image using a custom size with our shortcode.
If you were to disable the non-toolset plugins does the blurry images still appear?