My wife not comfortable putting our house as equity, therefore we are utilizing other options to fund investment properties. 

Now purchasing a home with cash is always good b/c obviously cash is king but also I think the part you might've missed is that, the money your utilizing on these home's won't actually be yours, but the banks or whatever institution you used to fix the home or make its value worth more.

For example, this can be adding square footage, adding an extra unit, or adding a pool in a STR market/luxury market.  

Or is it better to utilize different strategies?

Cost segregation utilizes the MACRS approach.

If you’re looking at retrofitting to separate heating for each unit (like furnaces or mini-splits), you might be looking at a higher upfront cost, but it can shift utility expenses to tenants and improve your NOI.I’d factor in boiler age and efficiency when analyzing deals and if it’s near the end of its life, negotiate a price reduction or a credit.

Kudos to you for utilizing and actually finding deals on FB.

@Alecia Loveless is correct--tenants need access 24/7 to their electric service panel, water and heat, assuming those are individual utilities for each unit. 

I’ve heard that this neighborhood doesn’t really have any problems from a social worker but outside areas aren’t good. 3/4 units are currently rented at $900 each, renters pay utilities.

Is there a possibility of getting utilities to the place?