I would go the conventional route on a loan, using LLC you won't be able to do that.

Hard money would be the easiest and most common route to fund the purchase/rehab.

Internships and apprenticeships are one route.

If I understand correctly your siblings goals are to sell their rental properties, use the funds to purchase a primary residence they'll eventually move into, and limit their tax liability correct?

Do not rely on your subcontractors to know/perform the code correctly for your area.

I’m looking to ensure I structure things correctly and attract the right partners.

I ended up having to pay for their tax preparer’s time to meet with me and make corrections.

Is this interpretation correct?

In the meantime, I would like to gain experience through employment with an existing real estate or property management company.Is there anyone out there that can provide me with some good advice/guidance as to the best and most practical route to achieve that goal?

I think you have a good plan, BRRRR is still a great route in the current market, and especially for the states you are already in - both Indiana and Georgia are very well positioned for BRRRR deals in my view / experience