They wouldn’t be able to volunteer as many application forms still ask whether you are a resident of the US (and can ask further questions about how long you’ve been in the US) or whether you can legally work. Organizations like hospitals or ones that work with children are considered the vulnerable sector so you would also need a criminal background check - which they don’t do if you lived in the US for less than a year. So basically, they’re also ineligible to do volunteer work.

In order to study ESL classes or be a student, they would be required to have a student visa - which conflicts with the K1. You also can’t have two types of visas at once. They have 90 days to plan their wedding and get hitched so the expectation would be that all your focus is on that, not school. In Andrei’s season, he wanted to apply to get his green card sooner so he could work, so they hustled on the wedding. Kirlyam only started ESL classes after she received her green card. So if they want to work or go to school, they need their wedding sooner so they can apply for their green card sooner too.