Yes, I checked shipwreck in game, there are wights, because shipwreck is a object of type shipwreck, not of type creatureBank.
So code must be like this:
{
"core:shipwreck": {
"types": {
"shipwreck": {
"levels": {
"chance": 40,
"guards": {
"amount": 50,
"type": "peasant"
}, {
"amount": 50,
"type": "peasant"
}, {
"amount": 50,
"type": "peasant"
}, {
"amount": 50,
"type": "peasant"
}, {
"amount": 50,
"type": "peasant"
}],
"combat_value": 300,
"reward": {
"resources": {
"gold": 15000
},
"artefacts": {
"class": "TREASURE"
}, {
"class": "MINOR"
}, {
"class": "TREASURE"
}, {
"class": "MINOR"
}],
"value": 17000
}
}, {
"chance": 40,
"guards": {
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
}],
"combat_value": 350,
"reward": {
"value": 20000,
"resources": {
"gold": 17000
},
"artefacts": {
"class": "MAJOR"
}, {
"class": "MINOR"
}, {
"class": "MINOR"
}, {
"class": "MINOR"
}]
}
}, {
"chance": 20,
"guards": {
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
},
{
"amount": 60,
"type": "peasant"
}, {
"amount": 60,
"type": "peasant"
}
],
"combat_value": 450,
"reward": {
"value": 26000,
"resources": {
"gold": 20000
},
"artefacts": {
"class": "MAJOR"
}, {
"class": "MINOR"
}, {
"class": "MINOR"
}, {
"class": "MAJOR"
}]
}
}]
},
}