Wikipedia backlinks are not bad for SEO, nor is having many Wikipedia backlinks. Wikipedia these days, is heavily patrolled by its corps of volunteer editors. So, if you embed a bunch of links into Wikipedia pointing to your site, there’s a pretty high chance they will all get removed. Hence, don’t waste your time on it.
There is no benefit/penalty in a ratio of do-follow to no-follow links. This is because Google no longer respects no-follow links. It will now make its own decisions whether to follow them or not.