Hope this was clear enough question LOL
Long story short, if you have the private key that you generated with vanitygen you're good to go. What wallet it's imported to is irrelevant until you want to see your NVOT then it'll need to be imported as a counterparty address to see the tokens.
Yes Right, The key here is the private key and if you lost that, it means trouble for you. Private key is generated by vanitygen and this is one of the first exchange which gives you access to the private key , thus making it much more secure for the end user.