Since I'm just starting, I'd appreciate any insights on:-The best ways to build trust and credibility as a beginner.

It sounds like @Ricardo Polanco is following the rules and just needs to let the OSE officers in for inspection.

My dads portion of our building will be gifted to me in the will FYI.As a real estate agent, I see 5% as a reasonable market appreciation.

I am looking to buy my first investment property and have heard a lot about  Fort WayneAs an out of state investor, I am looking to connect with investors/agents in the area to build further knowledge on specifics with the markets and hopefully bring business to in the future!

My long-term goal is to build a portfolio of multifamily rentals while also working as an agent helping investors scale their portfolios.Your experience sounds incredible!

Demo'd it and build a new 6,200 sq ft single fam. home (modular construction).

You are well on your way tho to wealth building.

Turn it into a duplex, and then build a duplex behind it. 

If you're going to do it alone, make sure you your due diligence: estoppels, inspection, review, consult with a local attorney familiar with the local regulations, etc. and good luck.

Sometimes going to local investor meet ups after investing for 15 years and building a large portfolio is a little disappointing.