I didn't believe this to be a support issue for WP Sync DB; on its own, the plugin works fine. Where I was having an issue was trying to bring it into my project using what I believed to be the proper method for use with Roots when a plugin wasn't available on packagist, thus I was looking for some guidance in that respect.
My assumption is, if I posted this on WP Sync DB's Github page, they'd direct me back here.
I was able to fix the issue by forking their repo and simply changing the constraint in their composer.json file. I just don't feel like this was the cleanest way of doing things. I also wanted to find a method that worked best moving forward, since many of these other plugins can include constraints which don't meet my project's requirements.