As far as a reasonable fee, I'd say it has to do with the value brought, and product level produced.

When the option is exercised there are no real estate agent fees.

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.

You should have $150k in mind though so you're prepared for worst case - and also to allow for soft costs (permit fees, etc.)$75-90k is typical for a garage conversion ADU in Sacramento.

In addition to state and local licensing fees, what broker will hold your license for free?

The gross amounts usually include cleaning fees, which you then pay right out to your cleaner, so factor that in when you figure out your net. 

Or, should i do the same exact concept except eliminate the holding company, and simply have 3 independent LLC's, all with me as the member, and the property management company handle all of the transactions and pay the property holding LLCs a fee each month? 

Just a heads-up—bonus depreciation can be claimed up to 60% for 2024, and it will drop down to 40% in 2025, so that’s something to keep in mind as you evaluate your options.I’m not endorsing any particular company, and I don’t receive referral fees for recommending the one I used.

I know there are the obvious PITIA items but what about property management fees (I plan on using a property manager), maintenance/repair allowance, and vacancy allowance?

How much cash have you already injected into the deal including soft costs like architectural fees, permitting, etc...that you can document.