console root account - I don't know if it's available to anyone in field. SSH service on storage cluster (reverse SSH tunnel to NetApp) can be enabled for NetApp Support, but generally SSH isn't available for remote access anyway.
cluster admin account - there's no lockout, but you can make the password very complex (e.g. 20 characters), and also you can eliminate the use of local cluster admin:
a) create a AD group, connect cluster to AD, add an admin group account as cluster admin, and then set vCenter plugin and other accounts to use that AD account.
b) block network access to cluster Management IP and VIP (normally it's blocked by default if you keep cluster management network on separate VLAN where only mNode and vCenter have access to, but if the case you have not implemented networking that way, then you could limit access to the IPs mNode, vCenter and perhaps 1-2 other hosts
IPMI ADMIN account - you can check in the IPMI UI (create a test account and try?), I don't remember this detail now (and there may be slight differences between different hardware models, e.g. H600 vs. H300 vs. H410, and IPMI f/w versions). As far as I know (I may be wrong), the only time IPMI admin account is used is when mNode/HCC upgrades BIOS and firmware, so if you don't have it on a secure network, you could probably enable this on demand (for f/w upgrades with HCC) and keep it disabled at other times.