I have a very nice three host VMware system paired up with an HP 3par SAN. I have several VM's that run and performance is great. I specifically have two linux mail servers that need to share Maildir's on an NFS mount. I currently have those two servers connected to a Netapp that is aging and running out of space. So I'm asking some solutions about what would be best to utilize the space on my 3par, but present that volume as NFS to the two mail servers. I could spin up a Linux box and mount it directly to a volume on the 3par and share it out via NFS, but I will lose those lovely Netapp snapshots that are accessible right from the directory path. Any ideas on how I could do that and keep some kind of snapshot solution in place?

Many years ago, I tried LVM snapshots (on LVM v2), and performance was terrible. I have not tried since. Maybe it has improved?
Could you not present ISCSI LUN to VMware VMs? If yes, does that give you what you are looking to achieve?

I can present a LUN from the 3par to a VM, but due to block storage only one VM can take advantage of it. Also it doesn't allow for directory level snapshots.

ZFS have cool snapshot ability. It is pretty close to NetApp features.
Please do not use BTRFS while it also has snapshots.

You can make the VM doing NFS server.
It will be single point of failure, but once it sits on redundant infrastructure, then who care ?

ZFS also has some NFS stuff built-in. I've never used it, I've used the OS NFS server ability.

If you want care about NFS redundancy anyway, I have a nice POC for multi-AZ (for AWS) NFS server (actually cluster).
Thankfully it had not gone to production, but no worth to see Stretch (active-active) NFS cluster with DRBD, GFS2.