Regulation Z (TILA) and the SAFE Act require that all mortgage loan applications include the MLO's unique identifier, which allows regulators and consumers to identify the MLO involved in the transaction.
"Each loan application must include the mortgage loan originator's name and unique identifier."
- 12 CFR § 1026.36(g); SAFE Act
Other listed information is not federally required on every mortgage application.
References:
CFPB, Loan Originator Identifier Requirements
SAFE MLO National Test Study Guide

Lenders may consider whether alimony, child support, or separate maintenance payments are likely to be consistently made, as this affects the borrower's ability to repay. Consideration of family status, phone listings, or age (except as required for legal capacity) is prohibited by the Equal Credit Opportunity Act (ECOA).
"A creditor must consider alimony, child support, or separate maintenance income to the extent that it is likely to be consistently received."
- 12 CFR § 1002.6(b)(5), Regulation B (ECOA)
References:
CFPB, Considering Alimony and Child Support
SAFE MLO National Test Study Guide

When there is no tax return history for a rental property, FHA guidelines require lenders to reduce the gross rental income by 25% to account for vacancies and maintenance.
"If there is no history of rental income on the borrower's tax returns, the lender must reduce the market rent by 25% before considering it as effective income."
- HUD 4000.1 FHA Single Family Housing Policy Handbook
References:
HUD 4000.1, FHA Rental Income Requirements (see Rental Income)

Standard guidelines recommend a 2-year history of commission income to count it as qualifying income.
However, lenders may consider a shorter history if there are positive factors to offset the shortfall. MLOs should always take the application and allow underwriting to review the overall credit risk.
"Generally, a minimum history of two years is recommended for commission income, but a shorter period may be considered with compensating factors."
- Fannie Mae Selling Guide, B3-3.1-05: Secondary Employment Income
References:
Fannie Mae, Commission Income Requirements
SAFE MLO National Test Study Guide

Under Regulation B (ECOA), creditors may ask about permanent residency or immigration status because this is relevant to the creditor's ability to enforce rights in the event of default. However, they may not ask about childbearing, and other options are either unnecessary or potentially discriminatory.
"A creditor may inquire about an applicant's permanent residency and immigration status."
- 12 CFR § 1002.5(e); Regulation B
References:
CFPB, ECOA Regulation B - Information a Lender May Request