Should I lease to 3 individuals when 1 doesn't qualify?

[David Moore]

I've received an application from 3 individuals who live together. The first two are a couple with a baby and would qualify for the home individually (each income separately is more than 3x monthly rent, etc.). The third person is a friend and live-in babysitter, has a part time job that doesn't meet the income requirement and had an eviction filed 3 years ago. The story is a relationship was ended and this person was left with an un-affordable lease.

I like these folks, they have been forthright about everything and the screening otherwise checks out, but not sure how to best handle the situation? It's obvious the couple are helping support this individual, but also receive babysitting while they both work full time. Could I make a stipulation that this person does not qualify on their own and must vacate if they do? Have the third person sign the lease or no?