From the options you mentioned, option 2 is what I would do in your case. There's no real drawback in using an RDM, you basically present a LUN to the ESXi host and attach it as an RDM to a VM (no SAN tools or management required). The only thing you cannot do with an RDM in physical (pass-trough) mode is to take VM snapshots, so you'd need to use a guest OS agent based backup tool.
Thanks for the reply. I'm open to other options if these are not the only ones. I just need a robust file server for lots of data.
I would be able to rely on SAN snapshots with the RDM so I don't know if it is a big deal to lose that functionality from the VM host.. And we prefer using a file-based backup utility for File-servers because of the indexing and version tracking features. So I won't miss vmdk snap or clone backups.
Does regular Vmotion and HA work with Physical RDM?