Valid reasons might include increased operating costs, property improvements, or market trends.Fairness and market rates: Rent increases should generally be reasonable and in line with market rates for similar properties in the area.

I also ask if they can reduce their minimum on my first investment with them.

Our hope is to find ways to increase cashflow with this property short term and reduce our bleeding, and also consider the cost associated to implement.The property is 2 units fully occupied. 1 tenant already rents out our garage for an extra cost, the other tenants are left with no additional storage outside their unit.

I would include the storage and bake it into the rent or not bother, you will have enough to account for as it is.

Or you can use your own proceeds (including the tax free cash from the sale of the primary residence side).

Check your state laws because I think you can charge 2x the first year but after that you have to reduce it to one month of rent.More important is solid screening, then policies and procedures to keep tenants on track so they don't get out of control.

The property is also in a great up and coming neighborhood, and its appreciated about $40k in equity in the last year, not including the ADU value add.

It does not matter if probate was opened or any notices sent out or anything similar.I understand your reasoning, but it is a constitutional due process issue that you cannot take someone's property away from them without due process of law, which includes notice.

Note: I am the GC and the Realtor so fees are already reduced. 

As to washer/dryer you'll need to look at similar size units in your market and see whether they include washer/dryer. hookups or nothing.