It is possible to exchange between ZEN<>stZEN through StakeHound and Copper. Average wait time with StakeHound is about 4 hours and you can exchange any amount you choose. Copper allows for instant swaps but please be aware they are not servicing small orders. Also note that both StakeHound and Copper require clients to go through the KYC/AML process.
Yes. If you are a US citizen and want to swap ZEN:stZEN on a 1:1 basis at StakeHound, you will need to do the KYC/AML process and hold an accredited investor status. Otherwise, US citizens and residents can freely buy and sell stZEN on SushiSwap.
Any transactions utilizing the Ethereum network incur ETH gas fees. If gas fees are a concern, you can choose to exchange ZEN<>stZEN directly with StakeHound at a 1:1 ratio. Ethereum gas fees can be tracked on Etherscan.
If you want to get stZEN using the ZEN that is currently running your nodes, you must give up the nodes and trade the ZEN for stZEN. If you want to keep the nodes you are currently running, the ZEN must stay in the same address, and you will need to use different ZEN or other new assets to get stZEN. Please be aware that you will automatically earn Horizen node rewards from stZEN by just holding it in your Ethereum wallet.