If your category page is paginated, you should use standard HTML rel=”next” and rel=”prev” elements to specify a relationship between the different category pages together with the canonical tags. This will ensure that Google will crawl and index much more of your website.

As for the parameters setting in Webmaster tools - you should only define these if you did not have the message from google displayed: "Currently Googlebot isn't experiencing problems with coverage of your site, so you don't need to configure URL parameters. (Incorrectly configuring parameters can result in pages from your site being dropped from our index, so we don't recommend you use this tool unless necessary.)". If that message is not displayed, then you can go ahead and add the parameters that don't change the content. Yes, your message parameter would be classed as non-content-changing.

The 301 redirect seems to be set up correctly from what you are describing.

Regarding the parameters setting in Webmaster tools - you should only define these if you did not have the message from google displayed: "Currently Googlebot isn't experiencing problems with coverage of your site, so you don't need to configure URL parameters. (Incorrectly configuring parameters can result in pages from your site being dropped from our index, so we don't recommend you use this tool unless necessary.)". If that message is not displayed, then you can go ahead and add the parameters that don't change the content. Yes, your message parameter would be classed as non-content-changing.

If your category page is paginated, you should use standard HTML rel=”next” and rel=”prev” elements to specify a relationship between the different category pages rather than the canonical tags. This will ensure that Google will crawl and index much more of your website.

As for the parameters setting in Webmaster tools - you should only define these if you did not have the message from google displayed: "Currently Googlebot isn't experiencing problems with coverage of your site, so you don't need to configure URL parameters. (Incorrectly configuring parameters can result in pages from your site being dropped from our index, so we don't recommend you use this tool unless necessary.)". If that message is not displayed, then you can go ahead and add the parameters that don't change the content. Yes, your message parameter would be classed as non-content-changing.

The 301 redirect seems to be set up correctly from what you are describing.

If your category page is paginated, you should use standard HTML rel=”next” and rel=”prev” elements to specify a relationship between the different category pages together with the canonical tags. This will ensure that Google will crawl and index much more of your website.

As for the parameters setting in Webmaster tools - you should only define these if you did not have the message from google displayed: "Currently Googlebot isn't experiencing problems with coverage of your site, so you don't need to configure URL parameters. (Incorrectly configuring parameters can result in pages from your site being dropped from our index, so we don't recommend you use this tool unless necessary.)". If that message is not displayed, then you can go ahead and add the parameters that don't change the content. Yes, your message parameter would be classed as non-content-changing.

The 301 redirect seems to be set up correctly from what you are describing.