While Limited Lodging is a permissible accessory use to Household Living, it is not permissible unless (i) the unit is the primary tenant's principal residence and (ii) the tenant lives in the unit for more than 6 months.

Or maybe its 6+ owner.according to municipal code 20.150.040:Household.

But mostly our household income has nearly doubled this year over last.

It doesn't seem like the father will stay at the property, and he is only applying along with his daughter so that their monthly household income will be at least 3x the monthly rental rate.

Clark County has a limit of 3 dogs per household, unless there is a special permit.

The make up households can change over time for various reasons.

A true ADA animal is highly trained, and not likely to soil carpet, however, it is under the same jurisdiction for damages as a regular household pet. 

As others have mentioned above the household formation ties into everything too as do the laws.  

Those who have them want to stay on Section 8, and therefore make sure to pay their rent on-timeYou have more demand for your property, as you've opened up to Section 8 tenants.Cons of Section 8:Property managers (that I interviewed) complained about the number of people living in the household and the state of the property upon turnover.

There is no line item on a tax return for your household rent.