So for the wallet name if lets say I pick bitnull then for btc I should generate bitnull-btc for eth it should be bitnull-eth etc?
Yes, you should generate a wallet for each active coin in your exchange using that format
What if one of those names is taken by someone else since the names are unique.
All wallets must have the same
VAULT-NAME. If a wallet using that
VAULT-NAME is taken, you have to change your
VAULT-NAME. This is why I recommend picking a
VAULT-NAME that is unique to your exchange from the beginning. Include numbers, dashes(
-), or underscores(
_) to your name to make it even more unique. For example, if your exchange name is
VAULT-NAME can be
bitnull-08_81. Keep in mind that the wallet name character limit is 20.