Does it matter that the Income-Driven Repayment Plan Request was done as part of a Direct Consolidation Loan Application?
No. Your wife will just have to click on "Direct Consolidations Loan Applications" under "My Loan Documents" to find the co-sign code, you will need.
Who all can co-sign for this?
Only the spouse of an applicant that initiated an Income-Driven Repayment Request.