With that said, the combination of poor credit history and land contract doesn't sound good. 

My net profit on top of the original $200K investment is $62.5K.4) wait at least 2 years5) after 2 years following the cashout refi, sell property at around ARV, $350K(I am actually skipping/combining a part where I do a Delayed Finance loan to get 75% of my money back asap after the initial acquisition, then do the cashout refi based on ARV after 6 months of seasoning).My first question is, are the above steps sound, strategically speaking?

Or do I buy out the owner and include the left over debt and rehabs at an all in $113K? 

Or do I buy out the owner and include the left over debt and rehabs at an all in $113K?

I plan on doing this by growing a large portfolio as quickly as possible while being careful not to over-leverage myself.In order to grow my portfolio as quickly as possible without over-extending my debt, I will create equity through value add opportunities.

While 99% of the rest of the people we know are still adding bad debt and justifying it because it is the normal path. 

When calculating vacancy and bad debt, do these have rule of thumb too? 

I'm thinking it would cost you at least $1,100-$1,200 a month just in debt coverage. 

I also recently became debt free, so the thought of having a mortgage on the rental and another mortgage on a house of my own scares me a little.

@William JenkinsDoesn't sound like you would use financing for the contemplated investment of retirements, but if you did it would need to be non-recourse (either via a Solo 401k or SDIRA) and if done via an IRA subject to Unrelated  Debt Finance Income tax.