Note rent minus piti does not equate to cash flow.  

Again, you market should dictate how you interact with tenants but generally speaking partial rent payments shouldn't be reasonable.

Rent growth is a function of supply, demand, and interest rates:- I'd ground any forecast by stating I expect national rents to rise on a pace more or less in line with inflation over any long time period. 2-3% per year.

'The property has been rented.

What rent collection software do you recommend and why?

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

We have our starter home currently rented out and can potentially move back. 

At annual rent increases, I do scour Zillow for market rents in the area, which I share with my tenants.

@Garry LawrenceDevin Moreno has a bunch of videos on rent-by-the-room strategy in Baltimore on hisYoutube channel.

Buy - Rehab - Rent - that has been the bulk of the work.