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if hatchlings are really sensitive to the heat (says member 'marisa')of like the lightbulbs, sun, etc. how hot should the temperatures be for them??

I suggest you read the care sheets on the main site. Many of these answers can easily be found simply by researching the vast wealth of knowledge that this site holds. Start here:
Main Site & Care Sheets

With that being said, the basking temp for hatchlings should be at least ten degrees high than their water temp, so around 88-90 (water temp needs to be around 78 degrees).