The answer is yes, Squirrly works okay with both WordPress SEO by Yoast and All in one.
[Update Squirrly SEO 2019]
However, even though it works, make sure you read the following.
Squirrly SEO 2019 (Squirrly SEO plugins starting version 9.1.00) is a complete redesign of all that we had before. Once you install the 2019 version, you have 100% everything you need for amazing WordPress SEO.
Squirrly has a feature called “Duplicate Removal” https://plugin.squirrly.co/duplicate-removal-tool/
if all the settings of Squirrly SEO are activated it will remove all counterparts going from Yoast into the source code of your page.
Therefore, to Google it will look like you’re using only one plugin.
Because of the Duplicate Removal we expect no conflicts. Yoast loads pretty slow, so that is the only thing where it could affect the performance of your pages.
Squirrly plugin loads super fast.
The only thing that sometimes seems like it’s loading slow in Squirrly is stuff coming over from the API, but Google doesn’t pick up on that and it is beyond their scope of interest. They just see that the site loads fast and that’s good enough for their algorithm.
Therefore, if you only use Squirrly SEO as a SEO plugin, Google will see that your WP site loads really fast. (compared to the same loading time, when you’d be using other SEO plugins)
We use Quick Redirect plugin on WordPress for re-directs. We’ve been using for years and does the job. Creates no problems in search console. Better UX with import / export features than what yoast plugin offers.
However, it is not mandatory to delete the yoast plugin.
[the old version of the article follows below. We still leave this in the Help Center for those with older versions of the plugin]
If you have Yoast or All in one SEO installed already, switch the Title and Description from Squirrly off.
You can always check for issues using the “Check for SEO issues in your site” button and Squirrly will guide you to fix the Meta duplicates.
Squirrly brings you all the updated WordPress SEO requirements and its main feature is to find you the best keywords and to help you optimize your articles for both humans and search engines.