Even if your GC is decent was able to get your job done in 100 days, if it doesn't resemble the comps in quality then your 300k exit is now 270k and with all the exit costs and holding costs your 40k expect profit is now under 10k. 

Quote from @Hector Espinosa: Hi,I'm negotiating a seller financing deal which may be my first one and would like to ask for some advise about and what are advantages and disadvantages about seller financing deals.These are the seller financing terms:House Price: $330,000.00 USD​ (Sellers still owe ~$301,000 USD)Down Payment: 5% = $16,500 USD​Loan Amount: $313, 500​ (Monthly payments will be amortized as a 30 years loan​)Interest Rate: 4.531%Balloon Loan Term: 5 YearsMonthly Payment (P&I): $1,594.24​Closing Costs:  ~$3300 ​Zip Code: 74105Observations:       * HVAC requires an update but pending to inspection (replacing with a new one will cost ~$10,000 - $15,000 USD )     * Expected Rent Income: $2,000- $2,300 but this is has been really complicated to get a good estimate because is all over the place in the different sites I have checked

If a seller doesn't know where they are going, you aren't buying their house.Also, you are probably expecting to get somewhere on the first call.

I don’t know what they expect to find.

I expect the house will appreciate by $80-100K immediately after putting $45K in renovation.

Is that typical for insurance placements in that market or is this the high end you would expect for this property? 

@Erlson Neba Much less stress and headaches than rentals especially for lower end areas where the ongoing maintenance will most likely diminish any return you may hope to make and where appreciation cannot be expected.

I expect that the Fed will drop rates next week and will continue to do so.

.- Ball park ranges - what can I expect the cost of this process to be?

Expect higher turnover as people renting rooms tend to move.