If one has a software system that eliminates human error, great. 

Looking to run internal analytics on my portfolio and have found both of these softwares.

You also want to account for your time, you also might add software or services that cost money.-5% Maintenance and Capex - realistically, this is too low.

Software/website/private contractors, around $40K/yr. 

Most investors on this site are residential with a few commercial sprinkled in so when BP develops software to use that is likely the main focus residential first.There are tons of software for commercial analysis to use out there. 

 We use buildium property managment software which allows tenants to set up online rent payment via ACH.

Are their specific methods or software used to monitor a projects schedule, keep GC's and subs accountable and all involved parties on task?

I am just saying that an average young sole proprietor may not be good with accounting and doing their own taxes and if they have they cannot afford to hire a tax professional and have multiple bank accounts they may not add up everything correctly or put things 100% correctly into tax software.

Does anyone have a recommendation on a software program to use so we can show potential buyers what the rehab will look like after completion.

Based on your level of interest & ability to use software/systems to scale you could manage a significant number of rentals.