Whereas I (and others) continually urge them to stop being lazy and do their own research....go on VRBO and ABNB and look at the competition. 1) What are they charging?

From my own personal experience and from others I think most reach the "tipping point" from self managing to using a PM somewhere between 5-15  units, especially if you have a W2 and want to continue to scale. 

This year, let's prioritize learning and adaptability, recognizing that continuous growth is key to staying ahead in an ever-evolving world.Networking and collaboration will be crucial as we navigate the changing landscapes of industries.

Huntsville, AL, showed—and continues to show—strong appreciation.

I'd expect prices to continue to appreciate, so the longer you delay, the more expensive things may be. 

To me STR and hotel caters to different groups of travelers and so despite competition as long as the travel demand of Hawaii remains (as you pointed out is a robust assumption) I think both will continue to do well.  

Will they continue paying market rent for a mismanaged property. 

I'd recommend the following:1) Continue to stay at home to save up more2) Buy the crappiest home in a good neighborhood, with financial help (parents?)

Interest rates atm seem quite high so will ride this out a bit longer (and ratios will continue to improve over time.) 

I'm sure the BP community would love to be continually updated as well on your progress.