Hello Klaus,
As long as you can provide a coin adapter for your coin’s wallet, you should not have any problem to only offer a wallet for that coin to your users. You will have to disable the built-in Bitcoin core node adapter (uncheck the “Enabled” option in the adapter settings).
If your coin is a direct fork of Bitcoin then you can connect to a running instance of your wallet using the Multi-adapter extension. Please refer to the documentation section “Coin Adapter development” for instructions.
If your wallet is different then you will need to implement parts of the coin adapter by extending the abstract class Dashed_Slug_Wallets_Coin_Adapter. Inspect the file wp-content/plugins/wallets/includes/coin-adapter.php and pay special attention to the methods under “// Wallet API”. You should create a class that extends these methods to connect to your wallet and to provide information about your coin. There instructions are in the PHPdoc comments and I remain available to answer any questions you may have.
To issue an initial amount to your users perhaps it’s best if you let the users create wallets, then, when everything is set up correctly, simply send a transaction to all the user deposit addresses.
Hope this is helpful. Do let me know if you have more questions or if any of this was not clear.
kind regards
Alex