Tax Returns For Green Card/Removal of Conditions

[Sarah&Facundo 595]

My fiance just got his K1 approved yesterday (YAY!) and will move to the US in the next few months.  As displayed at the interview, I make a lot more than the poverty line. However, I am considering getting my masters and received admission into a program beginning next September. Because it is a medical-based career, I will not be allowed to work that much during the program's 2.5 year duration. How would that effect my fiance's AOS and green card process?

 

Realistically in 2018, I will probably be fine because I will hit over the poverty line threshold before school even begins. So this is likely more a question of what happens when he gets to the Removal of Conditions stage. I will assume he has a job by then. Will his income count in our joint income? Will they review my tax returns from the few years prior to its removal and care that my income has been low? We will not be applying for any government benefits. I have savings because I was putting money away for grad school even before we decided to go the K1 route. Thanks!