Deleted SO widgets bundle but it’s still slowing my site way down

I was using Sydney and my site was running slow. So I bought a Premium Genesis theme and switched to that. I deleted all Site Origin plugins and rebuilt my site, but P3 Profiler still says that Sydney and SO Widgets Bundles are making my site lag. In my C-panel under themes it still looks like there is a ghost of a Sydney Child theme there. There are still functions.php and style.css files in that folder. Can I delete them or will that crash my site? I don’t know how else to get the SO stuff off my site for good.
Thanks for any help.