Many times these include underestimating Renovation Costs (Rehab Cost) especially worse if unexpected issues arise, improperly running the comps (Comparables) to determine the After Repair Value (ARV), or overlooking the (Holding Costs) that are paid monthly until the property is sold.

The delight regarding a wood frame house is that you can usually buy it cheaper than concrete block.

Also, it's been my experience that a tenant that pays late that much is living paycheck to paycheck and is just one unexpected bill (i.e. car repair, medical bill, etc) away from not paying rent at all. 

When prices are so low you need to be super diligent upfront as an unexpected capital expense can tank all your profits. 

I want to know from other investors, especially ones that work with wholesalers, if what I am planning on providing investors is overkill.Once I have a signed PSA, I plan on:paying for a title check (to make sure the title doesn't have any unexpected liens)scheduling a home inspectionhaving a general contractor provide a renovation estimate (labor & materials) for both a fix-n-flip and a rental renovationAn ARV appraisalI am planning on compiling all of this information, along with a copy of the PSA, a full RentFax report, pictures of the property, and a video walk-thru into an "investor packet" that will be emailed to my investor list.

Last month I had an unexpected replacement of sewer lateral $6500 and new HVAC of $4100. 

As with anything, you'll find people successful with it and some that are not successful - the factors above are what is important.Since you are using an IRA, make sure you have enough reserve funds in there to handle up front expenses or unexpected repairs.

An emergency fund is vital, so set some funds aside for maintenance and unexpected issues. 

Were there any unexpected costs during rehab?

They build in extra padding, so the unexpected does not derail the entire project.When creating your budget, make a room-by-room outline of work needed and estimated costs.