Gelcoat hairline cracks. As a boat ages and flexes, those cracks are going to appear. It's like noting that older people have wrinkly skin. They may be due to underlying structure flex, they may be due to expansion/contraction due to sitting in the sun, but for the most part, they're cosmetic. My '99 hull 03 has those cracks as well as the others you describe. I'm pretty sure you'll find them on any 20 yr old boat, I don't think it's anything to lose sleep over, and as a finding on a pre-purchase, not remarkable. You can repair them, but I believe you'll be chasing your tail.
I'd be more concerned about things like the condition of the deck drain hoses, bilge hoses, tank fill hoses, tank crossover hose, waste hoses, hose clamps. They're all at the age where they'll be due for replacement. There are a lot of hoses that are a real bear to access, and that translates to aggravation if DIY, or $$$ if yard work. Hand bilge pump manifold? Hoses there? Does the bilge smell bad? Has the rudder shoe/hardware been inspected/re-glassed/sealed? How's the deck under the winch? Are the penetrations sealed/potted? If the swim platform is still the hinged one, is it still watertight or are the hinges showing signs of water ingress into the attachment points/stains? Was the torsion coupler ever replaced? Life expectancy about 4000 hrs. Cutless bearings? OEM 8D batteries everywhere? Are the cored deck penetrations properly potted? If the doors are not Diamond Sea Glaze, have the hinge attachments been reinforced? Any staining? Include the Portuguese bridge door in that. Are the boarding gate hinges showing rust/stains? Any signs of looseness? I see in the photos the black vinyl trim is missing from the window frames. They were repainted? Unattractive, incomplete work. That trim is very difficult to source. Are the wiper arms intact? Look in the access ports on the flybridge structure- bone dry in there? Are there maintenance logs? Oil sample lab reports? Those kinds of things can be of consequence in considering a purchase, the gelcoat cracks, not so much.