I have a hard time justifying losing the interest rates you could get pre-2022 so I would lean away from selling.

Given that you plan to live in the South Carolina property for 2-3 years before turning it into a rental, I would lean towards using the HELOC for the down payment and getting a traditional mortgage. 

Each platform has its own audience and advantages.Personally, I'm leaning towards long-term rentals because it aligns better with my goals for stability and lower management effort.

I understand why they are used, but personally I would rather leave a voicemail and have a warm body call me back than deal with another automated system.Think of it this way: if someone is so urgently looking to sell a property that they can't wait for a call back in 1 business day, do you think they are going to sit through some automated system?  

This is leaning more towards MTR or LTR!

Would any body suggest best area to buy rental property in Jacksonville? 

Like @Michael Baum said, I would lean into the themes more in the home.

I heard not great, not terrible things, but now, I am leaning towards terrible.

I initially leaned towards townhomes because of the lower maintenance as I get acclimated to real estate investing.

I definitely am leaning toward out of state.