Note buying is a business and with any type of business you have to market and adjust to the market and develop new sources.  

My starting point for repairs is usually 5% of rent, but depending on the  age of the home, location of the home, and types of tenants I am attracting, I will adjust repairs up to 10-12% of gross rents.Have you incorporated taxes and insurance?

This is one reason why we find month-to-month agreements work better than long-term leases.About pest control service... either have the tenant pay for it directly to the pest control company or include it in the rent and adjust the rent upwards accordingly.

In a suburb you can use 3-5 miles.I try to look 6 months but sometimes have to go 1 year, never moreSquare footage is +/- 15%bedrooms don't have to be exact, it can be +/- 1 but that needs to be accounted for like everything else in your adjustments 

Meanwhile my realtor put in some work on the MLS and found 3 completely different ones in much more comparable areas but they refused to adjust the appraisal.

However if you keep at it and make the necessarily adjustments and pivots during your career you should be fine. 

I hope the zoning will be easy to adjust.

where can I find guidelines on how much to adjust on various features of a house?

A good PM will track the local market rents and will adjust your rents to keep pace on every new lease and will help you to keep your property at maximum profitability.I sincerely appreciate your giving nature...it really is rare these days. 

Our market is white hot, I actually look forward to someone leaving because the current market rates have shot up through the roof so we adjust accordingly.