I think this is a state law issue, but I am looking for any insight on what types of transactions activate dormant accounts generally speaking.

For example, would you say any transaction initiated by the customer should activate a dormant account, (ACH, POS, Wire Transfer, etc.)?

As you say, it is a state law issue and that is where your question might be answered. You might try re-posting in your state's forum.

Generally, a wire transfer or POS indicates the customer is still treating the account as active. Some ACH transactions; e.g. an ARC or a POP would make the same suggestion.

You might find that some states clarify what constitutes client initiated activity when it comes to auto debits and credits via ACH or other electronic means, so be sure to do your research.