California LLC's are a nightmare administratively and cost $800/year to the state.If you work with good counsel, you should have no significant risk of prohibited transactions, and the risk is exactly the same whether you write the checks or have a 3rd party custodian do so on behalf of your IRA. 

Does anyone know what I need to keep in terms of paperwork to write this off as a business expense when tax time rolls around again.

You would have to agree to a change (by adding an addendum), in writing. 

For some reason if you do, get it in writing!!!

Your agent can write the offer before your showing and then press send as soon as you see the inside.

Write offs .. get a cpa and learn all the tax codes and potential benefits 

I also write automatic increases into my leases.

I ended up buying a property via hard money with 15% down. the hard money lender gave me 85% of purchase (hence the 15% down) and 100% of rehab (meaning they paid for all that i had budgeted up front for rehab). i actually did a whole write up on this project. take a look at my profile and you'll see it there.

I would write it directly on the leases that if they do not keep the property reasonably clean, they will be asked to move.   

He said I was preapproved but I never received anything in writing.