Which is the suitable TMF API to module dunning attributes, like credit class id, credit class description etc?
First, please be aware that there is a Dunning API in preparation, but I'm afraid I don't have visibility as to its current status.
But regarding properties that could give guidance on whether to start dunning process, these would typically be associated with a Party or a PartyRole, depending on the context of the property. For example:
Suggest you take a look at the model and review the CreditRating and CreditProfile resources.
Hope it helps