I wouldn't recommend clear coating any plastic lenses.
The solvents in 2k clear coat can attack polycarbonate, and also they will be susceptible to constant stone chips, which will make them look even worse.
The crazing unfortunately is stress fractures within the polycarbonate lense, and cannot be reversed. You'd be better off searching for a pair of replacement headlights, or poor condition ones that you could split and swap the lenses over.
It's not a difficult job to do, but you do need to be patient, and very thorough when putting them back together. You need to use a sealant that stays soft, similar to windscreen sealant.