Sure enough the rehab ran over budget (we had a large contingency that was used up -- some due to contractor malfeasance, some due to pulling the trigger on big repairs like a new roof) and the revenues were right around expectations, maybe slightly below.  

As you indicated, make sure you leave something in the plan for contingencies (absolute minimum of 10%), and keep in mind the cost to hold during the time it's under construction and being marketed.Make a plan, check it twice, and decide if it's worth the effort. 

And yes I have done one in 50 years in the industry.Facts:1. purchase contract and gave 50k up front to bring tax's current. 2. it was all cash no contingencies.3. seller just goes dark no response to anything.4.

Are you going to negotiate inspection items, contingencies etc.

I have been able to buy houses of the MLS because their list price was good and I offered cash without contingencies.

Luckily, I did not include this unit in my underwriting when purchasing, so the survival of this property is not contingent on this situation.Continuing to optimize for management of the building when I move out, like moving everyone to online rent payments or adding remote accessible security cameras.Exploring opportunities to expand my portfolio—I've begun my hunt for my next 3 to 4-unit building to house hack, ideally in Lake View, North Center, or Ravenswood.This year taught me that real estate investing isn’t easy, but it’s undoubtedly worth it.

Having a contingency fund is key.

If the seller accepts the offer, (contingent on appraisal[as per court approval requirement]), How should i proceed in the situation.

Sellers rarely mind the low deposit and extended closing period due to the nature of the property, or at least they can be made aware of the fact that their lot has issues that will take MY time and MY money to solve and then they come around.My terms on the flip are: Minimum 10K spread between purchase and flip value.  1-2K deposit upfront to hold the property for 7 days then the deposit becomes non-refundable after the 7th day and the buyer has the same amount of time that I originally negotiated with seller typically 8-12 months(its a purchase contract but because of contingencies its essentially an option).  

As long as the buyer has not removed all contingencies and/or as long as the funds are at 1031 QI company then the Deferred Sales Trust can be used.