Ideally having worked remotely, held an intership before, or something equivalent. But I remember applying for my early dev jobs when every posting wanted 3 years experience. We don't exclude anyone by default, no hard requirements, a PR is is the best way to get our attention https://github.com/onaio.
No. I'm OK either with completion of an undergraduate degree in related field OR experience demonstrated through either 2-3 years working as a software engineer or equivalent open source software contributions.