Purchase price: $630,000 Cash invested: $120,000 Completely gutted this property, brand new electrical, furnace, propane, finished basement to create separate unit.New garage with rental unit.

It appears they quickly know how to adjust and select the right property.

Any referrals or recommendations for good and qualified brokers, sellers, property management companies, loan brokers, insurance brokers, mortgage brokers, contractors, etc.

My client would have been willing to pay up to the whole listed price because the property will be worth ~$525k ARV. 

Quote from @Alex Moazeni: You are making the common mistake of allowing a tenant to push you around.This is your property.

However, that obligation is waived if the tenant abandons the property without giving you notice of their forwarding address within 7 days of vacating.

I am currently in the planning phase of my real estate investment journey and had a few questions I’d like to ask someone more experienced.Would it be smarter to focus on paying down my own mortgage and then use a HELOC as a down payment for my first investment property, or should I simply use my savings for the down payment instead?

Jacksonville Attorney for Landlord Tenant Relations is Harry Heist, who has a website that you can download all these notices you will need for your property. https://evictforms.com/ 

Contact a real estate attorney in the county the property is in and have them do a property ownership search and lis pendens (lawsuit) check.

Also, I would look at rental rates to property values to determine if any areas are around the 1% rule.