I guess from a developers perspective, I'd take an educated guess that if you had 2 properties right next to each other, identical in size, lot size, bedrooms bathrooms etc, but 1 a MFH & the other a SFH, it seems that the SFH would sell for more, and probably cost less (less framing, doors, windows, appliances, boilers / furnaces / water tank etc

This does not necessarily require identical deeding. 

The best comps are nearly identical square footage, and if you find them you don't need to do all the math on $/sqft.  

In my area, that includes the following:Race, Color, Religion, Sex, Familial Status, National Origin, Disability, Military Status, Sexual Orientation, Age, Creed, Marital Status, Gender Identity, Source of Income, Immigration and Citizenship StatusBeing 19 y/o, the tenant is feels that this is unfair treatment based on age.

Unless you are investing with non-spousal partners, you don't need it for tax purposes because the deductions are really identical. 

I am not a lawyer, but it's important to be aware of the fair housing laws in your state and the laws that protect applicants from being discriminated against on the basis of race, color, religion, national origin, gender, age and other protected identities.

What is best plan of action to take on 2 identical 1975 2BR, 2BA, 2 car garage houses on same street in Buena Park, Orange County, CA that I am inheriting?  

@Dave Spooner I have not sold it, but an identical replica of the house ( this is a tract home) sold last month for 535K in worse conditions. 

In order to keep the liability protection on the homes owned through the LLC, I need to maintain "separate identities" between myself and my LLC. 

A professional manager will:1) Limit the risk of lawsuits and risk on tenant safety2) Perform home turns between tenants quicker than you can3) Screen tenants with advanced knowledge on Fair Housing Laws, identity theft, and filtering false references4) Be able to monitor and handle scams5) Provide you with the quickest eviction process if needed6) Have problem solving skills, so that most days you don't even know there was an issue because it resolved with little or no involvement from you.7) Have resources that include eviction attorney, repairs, cleaners, appliance repair, screening companies, mortgage properties, emergency line coverage.