I have no family-oriented background in real estate but I have a personal aim to inject this into my family's heritage starting with me as the first generation investor.

I'd rather not inject that much cash. 

Maybe you can locate an off market commercial property or partner with someone to inject cash into the business. 

Also consider when you renovate your initial returns in early years are lower bc of up front reno then improve after two to three years depending on what you inject as capital improvements.

@Brett Hulsebus what does equity injection mean exactly?

Some of the units there is quite a lot of deferred maintenance that the sellers have not addressed in the last 8 years of ownership.Acquiring the property with numbers above, injecting $100,000 into rehab, what could I expect the ARV or value of this property be once renovating and fully stabilized with good tenants?

Other investors are willing to split the equity in the partnership based on the the cash each person injected. 

I am looking to inject (contribute) some money into one of my LLC to finance some new acquisition this year.I am refinancing my home (that is under my own name) and will use the cash out as contribution into the LLC.It is my understanding that while you can't deduct new mortgage or refi anymore on your personal home, you can still deduct all its costs when it is used for investment (by deducting from the investment income/gain).What would be the proper way to document this transaction in addition to the schedule recording the contribution in the LLC book?

While you might have to inject some funds for repairs, the long-term plan would be to quickly get the property producing positive cashflow.

They could be as simple as just requiring surface injection by epoxy or could be major.