If Guarantor passes referencing can you still get RGI?

Guarantor 99% will pass referencing but the first of the two tenants just failed, on the basis of no income but she said she was not asked about her income and she has housing benefits.

Her fiance has housing benefits (they claim it jointly) and also a tattoo business, not sure how much proof he has with the income on the business regards to income as I think he’ll probably take a lot of the payment by cash not a card in a tattoo shop.

They have offered 3 months rent up front and are willing to pay every 3 months, in their current tenancy they pay every 6 months.

Just wandering, if they both fail due to not being able to prove affordability, is RGI still eligible if the Guarantor passes?

Or if 1 tenant passes on the affordability and Guarantor passes and she does not, is RGI still accepted in this situation?

I have had this. Can you visit them in their own home and get a sense of them and the state of their home. Its difficult to decide though and good tenants are scarce, but if they seem strsight forward and honest you may take them