Please let me know what gives you the impressions it's Wordfence that is using a large amount of memory - any charts/screenshots/etc that you can post will help us investigate this.
We already unschedule all cron jobs when you uninstall Wordfence. Please let me know, now that you've uninstalled Wordfence from the server and presumably deleted all source code, what is happening that leads you to believe that anything related to Wordfence is executing.
Thanks.