In addition to the original DMV titles, should I get a separate bill of sale for each unit? 

Originally posted by @Bruce Woodruff:Best way - Jackhammer it out and replace it, this time with adequate rebar and high pressure concrete.....Cheaper way - fill the cracks and paint it with deck paintCompromise - Lay tile on top (if you feel it's done moving) It's pretty uneven and separating. 

I would highly recommend setting aside the rental income in a separate account to build up a bit of a rainy day fund.

Are rest of utilities separately metered? 

Can I utilize the business bank account or would it be easier to have the funds separated personally since the income is technically not under the LLC?

However, if the duplex is “two separate 1/2 duplexes” each on a separate parcel/tax ID number, then no you can’t buy both with fha, period.  

Purchase price: $30,000 Cash invested: $10,000 Sale price: $60,000 The house was an old church parsonage, the church was purchased separately and the house relisted.

I also like one with a separate guest network so I can keep my smart home devices segregated.

Expensesget taxes from county. look at current valuation and you should have a good guess at how much it will go up based on purchase price.Find out what expenses are paid by LLVerify which utilities are separately metered; get average winter/summer monthly costs from utility company for any 'house' accountsGet quote per door from your insurance agentGet a quote from your landscaper (find out what they pay)Get a dumpster quote if you don't have city trash binsFind out if there is a parking lot sewer feeFind out rental registration requirements and costs (can be both county and muni)Income:Get the rent roll, In the contract require that you get estoppels signed by tenants and current owner saying amount of current rent, security deposit held, past due balances, and spelling out any promises for additional work/upgrades (there shouldn't be any). 

There is nothing wrong with continuing the collect the fee and holding it in a separate account while the tenants decides what they want to do.