If they have a good interest rate it might be worth looking to see if you could assume their loan to take advantage of the lower rate.  

.$300k mortgage at 7.25% (30-year): $2,046$300k mortgage at 7.6% (40-year): $1,996Technically, it lowers the monthly, but not by much once factoring in the rate adjustment.

As more people placed more properties in STR inventory, and as more municipalities taxed and regulated the industry, the profitability of the overall industry has reverted to a much more aligned (lower) risk adjusted return.  

These neighborhoods seem to fit my goals, especially with their lower crime rates and potential for growth.Do you think these are solid options, or would you recommend other neighborhoods in the Philadelphia area based on the price range and focus on appreciation?

I got 800+ credit and great mortgage offers so only reason im doing this seller financing idea is that its lower monthly cost

The result is typically less loan proceeds, lower rate, worse terms, etc.

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.

You could bring less down and possibly have a lower interest rate since you will be living there.

Contrary to most business lending, the REI industry has a lot of "non-bank" lenders that provide attractive loans that can lower your cost of capital and improve your profit/cash flow. 

Don't go for the cheapest (unless the price is lower because it is on sale), but also don't go for the most expensive.